Type IIA - Type IIB protein tyrosine kinase inhibitors hybridization as an efficient approach for potent multikinase inhibitor development: Design, synthesis, anti-proliferative activity, multikinase inhibitory activity and molecular modeling of novel indolinone-based ureides and amides

Mechanistic insight and structure activity relationship of isatin-based derivatives in development of anti-breast cancer agents

Breast cancer is most common in women and most difficult to manage that causes highest mortality and morbidity among all diseases and posing significant threat to mankind as well as burden on healthcare system. In 2020, 2.3 million women were diagnosed with breast cancer and it was responsible for 685,000 deaths globally, suggesting the severity of this disease. Apart from that, relapsing of cases and resistance among available anticancer drugs along with associated side effects making the situation even worse. Therefore, it is a global emergency to develop potent and safer antibreast cancer agents. Isatin is most versatile and flying one nucleus which is an integral competent and various anticancer agent in clinical practice and widely used by various research groups around the globe for development of novel, potent, and safer antibreast cancer agents. This review will shed light on the structural insights and antiproliferative potential of various isatin-based derivatives developed for targeting breast cancer in last three decades that will help researchers in design and development of novel, potent, and safer isatin-based antibreast cancer agents.

New 2-oxoindole derivatives as multiple PDGFRα/ß and VEGFR-2 tyrosine kinase inhibitors

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 (IC50 = 1.73 µM and 2.40 µM, respectively), and the benzyloxy derivative 9f was the next potent one with IC50 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 IC50 values of 7.41 nM, 6.18 nM, and 7.49 nM, respectively. In contrast, the reference compound Sunitinib exhibited IC50 values of 43.88 nM, 2.13 nM, and 78.46 nM against the same kinases. The derivative 9f followed closely, with IC50 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.

Phthalimide-tethered isatins as novel poly(ADP-ribose) polymerase inhibitors: Design, synthesis, biological evaluations, and molecular modeling investigations

Humanity is currently facing various diseases with significant mortality rates, particularly those associated with malignancies. Numerous enzymes and proteins have been identified as highly promising targets for the treatment of cancer. The poly(ADP-ribose) polymerases (PARPs) family comprises 17 members which are essential in DNA damage repair, allowing the survival of cancer cells. Unlike other PARP family members, PARP-1 and, to a lesser extent, PARP-2 show more than 90% activity in response to DNA damage. PARP-1 levels were shown to be elevated in various tumor cells, including breast, lung, ovarian, and prostate cancer and melanomas. Accordingly, novel series of phthalimide-tethered isatins (6a-n, 10a-e, and 11a-e) were synthesized as potential PARP-1 inhibitors endowed with anticancer activity. All the synthesized molecules were assessed against PARP-1, where compounds 6f and 10d showed nanomolar activities with IC50  = 15.56 ± 2.85 and 13.65 ± 1.42 nM, respectively. Also, the assessment of the antiproliferative effects of the synthesized isatins was conducted on four cancer cell lines: leukemia (K-562), liver (HepG2), and breast (MCF-7 and HCC1937) cancers. Superiorly, compounds 6f and 10d demonstrated submicromolar IC50 values against breast cancer MCF-7 (IC50  = 0.92 ± 0.18 and 0.67 ± 0.12 µM, respectively) and HCC1937 (IC50  = 0.88 ± 0.52 and 0.53 ± 0.11 µM, respectively) cell lines. In addition, compounds 6f and 10d induced arrest in the G2/M phase of the cell cycle as compared to untreated cells. Finally, in silico studies, including docking and molecular dynamic simulations, were performed to justify the biological results.

Receptor-based pharmacophore modeling, molecular docking, synthesis and biological evaluation of novel VEGFR-2, FGFR-1, and BRAF multi-kinase inhibitors

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

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.

Discovery of dual kinase inhibitors targeting VEGFR2 and FAK: structure-based pharmacophore modeling, virtual screening, and molecular docking studies

VEGFR2 and FAK signaling pathways are interconnected and have synergistic effects on tumor angiogenesis, growth, and metastasis. Thus, instead of the conventional targeting of each of these proteins individually with a specific inhibitor, the present work aimed to discover novel dual inhibitors targeting both VEGFR2 and FAK exploiting their association. To this end, receptor-based pharmacophore modeling technique was opted to generate 3D pharmacophore models for VEGFR2 and FAK type II kinase inhibitors. The generated pharmacophore models were validated by assessing their ability to discriminate between active and decoy compounds in a pre-compiled test set of VEGFR2 and FAK active compounds and decoys. ZINCPharmer web tool was then used to screen the ZINC database purchasable subset using the validated pharmacophore models retrieving 42,616 hits for VEGFR2 and 28,475 hits for FAK. Subsequently, they were filtered using various filters leaving 13,023 and 6,832 survived compounds for VEGFR2 and FAK, respectively, with 124 common compounds. Based on molecular docking simulations, thirteen compounds were found to satisfy all necessary interactions with VEGFR2 and FAK kinase domains. Thus, they are predicted to have a possible dual VEGFR2/FAK inhibitory activity. Finally, SwissADME web tool showed that compound ZINC09875266 is not only promising in terms of binding pattern to our target kinases, but also in terms of pharmacokinetic properties.

Identification of novel ureido benzothiophenes as dual VEGFR-2/EGFR anticancer agents

Presently, dual-targeting by a single small molecule stands out as a fruitful cancer-fighting strategy. Joining the global effort to fight cancer, a leading cause of death worldwide, we report in this study a novel set for benzothiophene-based aryl urea derivatives as potential anti-proliferative candidates endowed with dual VEGFR-2/EGFR inhibitory activities. The prepared ureido benzothiophenes 6a-r have been evaluated for their anticancer action on a panel of tumor cell lines, namely PanC-1, MCF-7, and HepG2 cells. Most newly synthesized benzo[b]thiophene ureas disclosed effective cytotoxic activities against the examined cancer cell lines. In particular, compound 6q, with an appended 4-trifluoromethoxy group on the terminal phenyl ring, exhibited the most significant cytotoxic activity in MCF-7 with IC50 3.86 ± 0.72 ug/mL; IC50 of 3.65 ± 0.18 ug/ml in PanC-1 cell line and an IC50 of 4.78 ± 0.06 ug/ml in HepG2. After that, derivatives that exhibited the most potent cytotoxic activities (6g, 6j, 6q, and 6r) were further evaluated as VEGFR-2 and EGFR inhibitors. Fortunately, they displayed low nanomolar IC50 values against both enzymes, where compound 6q emerged to possess superior inhibitory effects towards both EGFR and VEGFR-2 with IC50 46.6 nM and 11.3 nM simultaneously compared to the reference medications Erlotinib and Sorafenib, respectively. The docked structure of 6q within the catalytic region of VEGFR-2 and EGFR kinases was acquired and studied so that we could investigate potential binding mechanisms for the target ureido benzothiophenes. Hence, the benzothiophene-based aryl urea scaffold has great potential for advancing the development of highly effective dual inhibitors targeting both EGFR and VEGFR-2, which can serve as effective candidates for anticancer therapy.

Rational design and synthesis of novel quinazolinone N-acetohydrazides as type II multi-kinase inhibitors and potential anticancer agents

In the current investigation, a new class of quinazolinone N-acetohydrazides 9a-v was designed as type II multi-kinase inhibitors. The target quinazolinones were tailored so that the quinazolinone moiety would occupy the front pocket of the binding sites of VEGFR-2, FGFR-1 and BRAF kinases, meanwhile, the phenyl group at position 2 would act as a spacer which was functionalized at position 4 with an N-acetohydrazide linker that could achieve the key interactions with the essential gate area amino acids. The hydrazide moiety was linked to diverse aryl derivatives to occupy the hydrophobic back pocket of the DFG-out conformation of target kinases. The synthesized quinazolinone derivatives 9a-v demonstrated moderate to potent VEGFR-2 inhibitory activity with IC50 spanning from 0.29 to 5.17 µM. Further evaluation of the most potent derivatives on FGFR-1, BRAFWT and BRAFV600E showed that the quinazolinone N-acetohydrazides 9d, 9e, 9f, 9l and 9m have a potent multi-kinase inhibitory activity. Concurrently, 9b, 9d, 9e, 9k, 9l, 9o, 9q demonstrated potent growth inhibitory activity on NCI cancer cell lines with GI50 reaching 0.72 µM. In addition, compound 9e arrested the cell cycle progression in MDA-MB-231 cell line at the G2/M phase and showed the ability to induce apoptosis.

Recent Development in the Search for Epidermal Growth Factor Receptor (EGFR) Inhibitors based on the Indole Pharmacophore

The signal transduction and cell proliferation are regulated by the epidermal growth factor receptor. The proliferation of tumor cells, apoptosis, invasion, and angiogenesis is inhibited by the epidermal growth factor receptor. Thus, breast cancer, non-small cell lung cancer, cervical cancer, glioma, and bladder cancer can be treated by targeting the epidermal growth factor receptor. Although third-generation epidermal growth factor receptor inhibitors are potent drugs, patients exhibit drug resistance after treatment. Thus, the search for new drugs is being continued. Among the different potent epidermal growth factor receptor inhibitors, we have reviewed the indole-based inhibitors. We have discussed the structure-activity relationship of the compounds with the active sites of the epidermal growth factor receptor receptors, their synthesis, and molecular docking studies.

Advances of antitumor drug discovery in traditional Chinese medicine and natural active products by using multi-active components combination

The antitumor efficacy of Chinese herbal medicines has been widely recognized. Leading compounds such as sterols, glycosides, flavonoids, alkaloids, terpenoids, phenylpropanoids, and polyketides constitute their complex active components. The antitumor monomers derived from Chinese medicine possess an attractive anticancer activity. However, their use was limited by low bioavailability, significant toxicity, and side effects, hindering their clinical applications. Recently, new chemical entities have been designed and synthesized by combining natural drugs with other small drug molecules or active moieties to improve the antitumor activity and selectivity, and reduce side effects. Such a novel conjugated drug that can interact with several vital biological targets in cells may have a more significant or synergistic anticancer activity than a single-molecule drug. In addition, antitumor conjugates could be obtained by combining pharmacophores containing two or more known drugs or leading compounds. Based on these studies, the new drug research and development could be greatly shortened. This study reviews the research progress of conjugates with antitumor activity based on Chinese herbal medicine. It is expected to serve as a valuable reference to antitumor drug research and clinical application of traditional Chinese medicine.

Novel hydrazone-isatin derivatives as potential EGFR inhibitors: Synthesis and in vitro pharmacological profiling

Merging isatin and arylhydrazone moieties constitutes an efficient strategy to access new potential anticancer derivatives. Consequently, 14 hydrazone-isatin derivatives were synthesized and evaluated for their antiproliferative activity against the NCI-60 cancer cell line panel. A kinase assay demonstrated that compound VIIIb inhibited the epidermal growth factor receptor (EGFR), which was confirmed by docking studies, molecular dynamics, and binding free energy calculations. Further characterizations showed that this compound possesses drug-likeness properties, showed a significant decrease of the cell population in the G2/M phase and led to a significant increase in early and late apoptosis, comparable to erlotinib. Also, VIIIb increased the expression of caspase-3 and Bax and decreased the expression of Bcl-2, confirming its potential as a new proapoptotic compound.

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.

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.

Design and synthesis of some new 6-bromo-2-(pyridin-3-yl)-4-substituted quinazolines as multi tyrosine kinase inhibitors

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 (IC₅₀ = 1.54 µM) relative to Lapatinib (IC₅₀ = 0.48 µM), whereas compounds 9d and 11c showed a superior cytotoxicity towards MDA-MB-231 (IC₅₀ = 2.67 and 1.75 µM, respectively) in comparison to Lapatinib (IC₅₀ = 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 (IC₅₀ = 79.80, 50.22 and 78.02 nM, respectively) relative to Sorafenib (IC₅₀ = 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 (IC₅₀ = 17.51 and 5.56 µM, respectively) and 14c (IC₅₀ = 10.40 and 3.37 µM, respectively) compared to Sorafenib (IC₅₀ = 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.

New fluorinated diarylureas linked to pyrrolo[2,3-d]pyrimidine scaffold as VEGFR-2 inhibitors: Molecular docking and biological evaluation

A series of pyrrolo[2,3-d]pyrimidine linked to diarylureas were previously discovered by our group as sorafenib fused congeners, which were endowed with more potent activity as inhibitors to vascular endothelial growth factor receptor (VEGFR2) than sorafenib. Based on these results and on the observation that the fluorinated regorafenib displayed higher VEGFR2 inhibitory activity relative to sorafenib. Therefore, in this study, we sought to develop more potent pyrrolopyrimidine surrogates through introduction of fluorine atom at the phenyl moiety near to the urea moiety mimicking regorafenib. We hypothesized that this would improve the compounds potency. Surprisingly, Compound9epossessed better VEGFR2 inhibitory activity (IC₅₀ = 52.4 nM) compared to standard drug sorafenib, whereas compounds (9b,d and f) showed moderate inhibitory activity. The newly synthesized compounds were tested on 60 human cancer cell lines. Field alignment and a molecular docking study of these compounds into the inactive conformation of VEGFR2 was performed, and theoretical ADME properties were determined.

Identification of 3-(piperazinylmethyl)benzofuran derivatives as novel type II CDK2 inhibitors: design, synthesis, biological evaluation, and in silico insights

In the current work, a hybridisation strategy was adopted between the privileged building blocks, benzofuran and piperazine, with the aim of designing novel CDK2 type II inhibitors. The hybrid structures were linked to different aromatic semicarbazide, thiosemicarbazide, or acylhydrazone tails to anchor the designed inhibitors onto the CDK2 kinase domain. The designed compounds showed promising CDK2 inhibitory activity. Compounds 9h, 11d, 11e and 13c showed potent inhibitory activity (IC₅₀ of 40.91, 41.70, 46.88, and 52.63 nM, respectively) compared to staurosporine (IC₅₀ of 56.76 nM). Moreover, benzofurans 9e, 9h, 11d, and 13b showed promising antiproliferative activities towards different cancer cell lines, and non-significant cytotoxicity on normal lung fibroblasts MRC-5 cell line. Furthermore, a cell cycle analysis as well as Annexin V-FITC apoptosis assay on Panc-1 cell line were performed. Molecular docking simulations were performed to explore the ability of target benzofurans to adopt the common binding pattern of CDK2 type II inhibitors.

A Mini Review on Isatin, an Anticancer Scaffold with Potential Activities against Neglected Tropical Diseases (NTDs)

Isatin, chemically an indole-1H-2,3-dione, is recognised as one of the most attractive therapeutic fragments in drug design and development. The template has turned out to be exceptionally useful for developing new anticancer scaffolds, as evidenced by the increasing number of isatin-based molecules which are either in clinical use or in trials. Apart from its promising antiproliferative properties, isatin has shown potential in treating Neglected Tropical Diseases (NTDs) not only as a parent core, but also by attenuating the activities of various pharmacophores. The objective of this mini-review is to keep readers up to date on the latest developments in the biological potential of isatin-based scaffolds, targeting cancer and NTDs such as tuberculosis, malaria, and microbial infections.

Natural inspired piperine-based ureas and amides as novel antitumor agents towards breast cancer

In this work, the natural piperine moiety was utilised to develop two sets of piperine-based amides (5a–i) and ureas (8a–y) as potential anticancer agents. The anticancer action was assessed against triple negative breast cancer (TNBC) MDA-MB-231, ovarian A2780CP and hepatocellular HepG2 cancer cell lines. In particular, 8q stood out as the most potent anti-proliferative analogue against TNBC MDA-MB-231 cells with IC₅₀ equals 18.7 µM, which is better than that of piperine (IC₅₀ = 47.8 µM) and 5-FU (IC₅₀ = 38.5 µM). Furthermore, 8q was investigated for its possible mechanism of action in MDA-MB-231 cells via Annexin V-FITC apoptosis assay and cell cycle analysis. Moreover, an in-silico analysis has proposed VEGFR-2 as a probable enzymatic target for piperine-based derivatives, and then has explored the binding interactions within VEGFR-2 active site (PDB:4ASD). Finally, an in vitro VEGFR-2 inhibition assay was performed to validate the in silico findings, where 8q showed good VEGFR-2 inhibitory activity with IC₅₀ = 231 nM.

Design, synthesis, anticancer, and docking of some S- and/or N-heterocyclic derivatives as VEGFR-2 inhibitors

Novel heterocyclic derivatives (4-22) were designed, synthesized, and evaluated against hepatocellular carcinoma type (HepG2) and breast cancer (MCF-7) cells, targeting the VEGFR-2 enzyme. Compounds 18, 10, 13, 11, and 14 were found to be the most potent derivatives against both the HepG2 and MCF-7 cancer cell lines, with GI₅₀  = 2.11, 2.54 µM, 3.16, 3.64 µM, 3.24, 6.99 µM, 7.41, 6.49 µM and 8.08, 10.46 µM, respectively. Compounds 18 and 10 showed higher activities against both HepG2 and MCF-7 cells than sorafenib (GI₅₀  = 9.18, 5.47 µM, respectively) and doxorubicin (GI₅₀  = 7.94, 8.07 µM, respectively). Compounds 13, 11, and 14 showed higher activities than sorafenib against HepG2 cancer cells, but lower activities against MCF-7 cells. Compounds 18, 13, and 10 were more potent than sorafenib, inhibiting vascular endothelial growth factor receptor-2 (VEGFR-2) at GI₅₀ values of 0.05, 0.06, and 0.08 µM, respectively. Compound 11 inhibited VEGFR-2 at an IC₅₀ value of 0.10 µM, which is equipotent to sorafenib. Compound 14 inhibited VEGFR-2 at an IC₅₀ value of 0.11 µM, which is nearly equipotent to sorafenib. The tested compounds have more selectivity against cancer cell lines. Compounds 18, 10, 13, 11, and 14 are, respectively, 16.76, 9.24, 6.06, 2.78, and 2.85 times more toxic in HePpG2 cancer cells than in VERO normal cells. Also, compounds 18, 10, 13, 11, and 14 are, respectively, 14.07, 8.02, 2.81, 3.18, and 2.20 times more toxic in MCF-7 than in VERO normal cells. The most active compounds, 10, 13, and 18, showed a good ADMET (absorption, distribution, metabolism, excretion, and toxicity) profile.

Novel oxindole/benzofuran hybrids as potential dual CDK2/GSK-3β inhibitors targeting breast cancer: design, synthesis, biological evaluation, and in silico studies

The serine/threonine protein kinases CDK2 and GSK-3β are key oncotargets in breast cancer cell lines, therefore, in the present study three series of oxindole-benzofuran hybrids were designed and synthesised as dual CDK2/GSK-3β inhibitors targeting breast cancer (5a-g, 7a-h, and 13a-b). The N1 -unsubstituted oxindole derivatives, series 5, showed moderate to potent activity on both MCF-7 and T-47D breast cancer cell lines. Compounds 5d-f showed the most potent cytotoxic activity with IC50 of 3.41, 3.45 and 2.27 μM, respectively, on MCF-7 and of 3.82, 4.53 and 7.80 μM, respectively, on T-47D cell lines, in comparison to the used reference standard (staurosporine) IC50 of 4.81 and 4.34 μM, respectively. On the other hand, the N1 -substituted oxindole derivatives, series 7 and 13, showed moderate to weak cytotoxic activity on both breast cancer cell lines. CDK2 and GSK-3β enzyme inhibition assay of series 5 revealed that compounds 5d and 5f are showing potent dual CDK2/GSK-3β inhibitory activity with IC50 of 37.77 and 52.75 nM, respectively, on CDK2 and 32.09 and 40.13 nM, respectively, on GSK-3β. The most potent compounds 5d-f caused cell cycle arrest in the G2/M phase in MCF-7 cells inducing cell apoptosis because of the CDK2/GSK-3β inhibition. Molecular docking studies showed that the newly synthesised N1 -unsubstituted oxindole hybrids have comparable binding patterns in both CDK2 and GSK-3β. The oxindole ring is accommodated in the hinge region interacting through hydrogen bonding with the backbone CO and NH of the key amino acids Glu81 and Leu83, respectively, in CDK2 and Asp133 and Val135, respectively, in GSK-3β. Whereas, in series 7 and 13, the N1 -substitutions on the oxindole nucleus hinder the compounds from achieving these key interactions with hinge region amino acids what rationalises their moderate to low anti-proliferative activity.

Development of 3-methyl/3-(morpholinomethyl)benzofuran derivatives as novel antitumor agents towards non-small cell lung cancer cells

As one of the most lethal malignancies, lung cancer is considered to account for approximately one-fifth of all malignant tumours-related deaths worldwide. This study reports the synthesis and in vitro biological assessment of two sets of 3-methylbenzofurans (4a-d, 6a-c, 8a-c and 11) and 3-(morpholinomethyl)benzofurans (15a-c, 16a-b, 17a-b and 18) as potential anticancer agents towards non-small cell lung carcinoma A549 and NCI-H23 cell lines, with VEGFR-2 inhibitory activity. The target benzofuran-based derivatives efficiently inhibited the growth of both A549 and NCI-H23 cell lines with IC50 spanning in ranges 1.48-47.02 and 0.49-68.9 µM, respectively. The three most active benzofurans (4b, 15a and 16a) were further investigated for their effects on the cell cycle progression and apoptosis in A549 (for 4b) and NCI-H23 (for 15a and 16a) cell lines. Furthermore, benzofurans 4b, 15a and 16a displayed good VEGFR-2 inhibitory activity with IC50 equal 77.97, 132.5 and 45.4 nM, respectively.

Development of 2-oindolin-3-ylidene-indole-3-carbohydrazide derivatives as novel apoptotic and anti-proliferative agents towards colorectal cancer cells

Mitochondrial anti-apoptotic Bcl2 and BclxL proteins, are overexpressed in multiple tumour types, and has been involved in the progression and survival of malignant cells. Therefore, inhibition of such proteins has become a validated and attractive target for anticancer drug discovery. In this manner, the present studies developed a series of novel isatin-indole conjugates (7a-j and 9a-e) as potential anticancer Bcl2 and BclxL inhibitors. The progression of the two examined colorectal cancer cell lines was significantly inhibited by all of the prepared compounds with IC₅₀ ranges132-611 nM compared to IC₅₀ = 4.6 µM for 5FU, against HT-29 and IC₅₀ ranges 37-468 nM compared to IC₅₀ = 1.5 µM for 5FU, against SW-620. Thereafter, compounds 7c and 7g were selected for further investigations. Interestingly, both compounds exhibited selective cytotoxicity against both cell lines with high safety to normal fibroblast (HFF-1). In addition, both compounds 7c and 7g induced apoptosis and inhibited Bcl2 and BclxL expression in a dose-dependent manner. Collectively, the high potency and selective cytotoxicity suggested that conjugates 7c and 7g could be a starting point for further optimisation to develop novel pro-apoptotic and antitumor agents towards colon cancer.

Discovery of new quinoxaline-2(1H)-one-based anticancer agents targeting VEGFR-2 as inhibitors: Design, synthesis, and anti-proliferative evaluation

VEGF/VEGFR2 pathway is the crucial therapeutic target in the treatment of cancer. So that, a new series of quinoxaline-2(1H)-one derivatives were designed and synthesized. The synthesized compounds were tested against three human cancer cell lines (HepG-2, MCF-7 and HCT-116) aiming to evaluate its anti-proliferative activities. Doxorubicin as a universal anticancer drug and sorafenib as a potent VEGFR-2 inhibitor were used as positive controls. The data obtained from biological activity were found highly correlated with that obtained from molecular modeling studies. The most sensitive cell line to the influence of our new derivatives was HCT-116. Compounds 13_b, 15, 16_e and 17_b exert the highest cytotoxic activities against the tested cell lines. Overall, compound 15 was the most active member with IC₅₀ values of 5.30, 2.20, 5.50 µM against HepG-2, MCF-7 and HCT-116, respectively. Compounds 15 and 17_b showed better anti-proliferative activities than doxorubicin and sorafenib against the three cancer cell lines. Additionally, compound 16_e showed better anti-proliferative activities than doxorubicin and sorafenib against HepG-2 and HCT-116 but exhibited lower activity against MCF-7 cell line. In addition, the most promising members were further evaluated for their inhibitory activities against VEGFR-2. Compounds 15 and 17_b potently inhibited VEGFR-2 at lower IC₅₀ values of 1.09 and 1.19 µM, respectively, compared to sorafenib (IC₅₀ = 1.27 µM). Moreover, docking studies were conducted to investigate the binding pattern of the synthesized compounds against the prospective molecular target VEGFR-2.

Design, synthesis, and biological evaluation of novel EGFR inhibitors containing 5-chloro-3-hydroxymethyl-indole-2-carboxamide scaffold with apoptotic antiproliferative activity

New EGFR inhibitor series of fifteen 5-chloro-3-hydroxymethyl-indole-2-carboxamide derivatives has been designed, synthesized, and tested for antiproliferative activity against a panel of cancer cell lines. The results showed that p-substituted phenethyl derivatives 10, 11, 13, 15 and 17-19 showed superior antiproliferative activity compared to their m-substituted counterparts 12, 14, 16 and 20. Compounds 15, 16, 19 and 20 displayed promising EGFR inhibitory activity as well as an increase in caspase 3 levels. Compounds 15 and 19 increased caspase-8 and 9 levels, as well as inducing Bax and decreasing Bcl-2 protein levels. Compound 19 demonstrated cell cycle arrest at pre-G1 and G2/M phases. The results of the docking study into the active site of EGFR revealed strong fitting of the new compounds with higher binding affinities compared to erlotinib.

Structural insights of oxindole based kinase inhibitors as anticancer agents: Recent advances

Small-molecule kinase inhibitors are being continuously explored as new anticancer therapeutics. Kinases are the phosphorylating enzymes which regulate numerous cellular functions such as proliferation, differentiation, migration, metabolism, and angiogenesis by activating several signalling pathways. Kinases have also been frequently found to be deregulated and overexpressed in cancerous tissues. Therefore, modulating the kinase activity by employing small molecules has emerged as a strategic approach for cancer treatment. On the other hand, oxindole motifs have surfaced as privileged scaffolds with significant multi-kinase inhibitory activity. The present review summarises recent advances in the development of oxindole based kinase inhibitors. The role of distinguished structural frameworks of oxindoles, such as 3-alkenyl oxindoles, spirooxindoles, 3-iminooxindoles and similar hydrazone derivatives have been described based on their kinase inhibition potential. Furthermore, the design strategies, mechanism of actions, structure activity relationships (SARs) and their mode of interaction with target protein have been critically highlighted.

Discovery of 4-alkoxy-2-aryl-6,7-dimethoxyquinolines as a new class of topoisomerase I inhibitors endowed with potent in vitro anticancer activity

In our attempt to develop potential anticancer agents targeting Topoisomerase I (TOP1), two novel series of 4-alkoxy-2-arylquinolines 14a-p and 19a-c were designed and synthesized based on structure activity relationships of the reported TOP1 inhibitors and structural features required for stabilization of TOP1-DNA cleavage complexes (TOP1ccs). The in vitro anticancer activity of these two series of compounds was evaluated at one dose level using NCI-60 cancer cell lines panel. Compounds 14e-h and 14m-p, with p-substituted phenyl at C2 and propyl linker at C4, were the most potent and were selected for assay at five doses level in which they exhibited potent anticancer activity at sub-micromolar level against diverse cancer cell lines. Compound 14m was the most potent with full panel GI₅₀ MG-MID 1.26 μM and the most sensitive cancers were colon cancer, leukemia and melanoma with GI₅₀ MG-MID 0.875, 0.904 and 0.926 μM, respectively. Melanoma (LOX IMVI) was the most sensitive cell line to all tested compounds displaying GI₅₀ from 0.116 to 0.227 μM, TGI from 0.275 to 0.592 μM and LC₅₀ at sub-micromolar concentration against almost of the tested compounds. Compounds 14e-h and 14m-p were assayed using TOP1-mediated DNA cleavage assay to evaluate their ability to stabilize TOP1ccs resulting in cancer cell death. The morpholino analogs 14h and 14p exhibited moderate TOP1 inhibitory activity compared to 1 μM camptothecin suggesting their use as lead compounds that can be optimized for the development of more potent anticancer agents with potential TOP1 inhibitory activity. Finally, Swiss ADME online web tool predicted that compounds 14h and 14p possessed good oral bioavailability and druglikeness characteristics.

Recent advances of dual FGFR inhibitors as a novel therapy for cancer

Fibroblast growth factor receptor (FGFR) includes four highly conserved transmembrane receptor tyrosine kinases (FGFR1-4). FGF and FGFR regulate many biological processes, such as angiogenesis, wound healing and tissue regeneration. The abnormal expression of FGFR is related to the tumorigenesis, tumor progression and drug resistance of anti-tumor treatments in many types of tumors. Nowadays there are many anti-cancer drugs targeting FGFR. However, traditional single-target anti-tumor drugs are easy to acquire drug resistance. The therapeutic effect can be enhanced by simultaneously inhibiting FGFR and another target (such as VEGFR, EGFR, PI3K, CSF-1R, etc.). We know drug combination can bring problems such as drug interactions. Therefore, the development of FGFR dual target inhibitors is an important direction. In this paper, we reviewed the research on dual FGFR inhibitors in recent years and made brief comments on them.

Biphenylurea/thiourea derivatives tagged with heteroarylsulfonamide motifs as novel VEGFR2 inhibitors; Design, synthesis and anti-angiogenic activity

Anti-angiogenesis targeting vascular endothelial growth factor receptor 2 (VEGFR2) has emerged as a vital tool for cancer treatment. In this study, a new series of biphenylurea/thiourea derivatives tagged with heteroarylsulfonamide motifs (3a-l) was designed and synthesized as novel VEGFR2 inhibitors. The biochemical profiles of the target compounds were investigated using viability of human umbilical vascular endothelial cells (HUVECs), migration assay and Western blot using sorafenib as reference antiangiogenic drug. Most of the tested compounds exhibited significant antiproliferative activity against HUVECs, where compounds 3a, 3e, 3g, 3h and 3l exhibited better antiproliferative activity than sorafenib. All compounds significantly inhibited VEGF stimulated migration of HUVECs at 10 µM dose with (3a, 3e, 3g, 3h and 3l) showing better or comparable inhibitory activities to that of sorafenib. Moreover, Western blotting analysis confirmed antiangiogenic effect of those compounds with significant reduction in the level of VEGFR-2 compared to sorafenib. Finally, cytotoxicity screening of these derivatives against four cancer cells and RPE1 as normal cell line was performed. The mechanistic effectiveness in cell cycle progression and apoptotic induction were evaluated for the promising compound 3e due to its remarkable cytotoxic activity against tested cancer cell lines and significant VEGFR-2 inhibition. Flow cytometric analysis showed that compound 3e induced cell growth arrest at G2/M phase and stimulated the apoptotic death of HepG2 cells.

New quinoxaline-2(1H)-ones as potential VEGFR-2 inhibitors: design, synthesis, molecular docking, ADMET profile and anti-proliferative evaluations

Eleven new quinoxaline derivatives were designed and synthesized as modified VEGFR-2 inhibitors of our previous work.

Novel [(N-alkyl-3-indolylmethylene)hydrazono]oxindoles arrest cell cycle and induce cell apoptosis by inhibiting CDK2 and Bcl-2: synthesis, biological evaluation and in silico studies

As a continuation for our previous work, a novel set of N-alkylindole-isatin conjugates (7, 8a-c, 9 and 10a-e) is here designed and synthesised with the prime aim to develop more efficient isatin-based antitumor candidates. Utilising the SAR outputs from the previous study, our design here is based on appending four alkyl groups with different length (ethyl and n-propyl), bulkiness (iso-propyl) and unsaturation (allyl) on N-1 of indole motif, with subsequent conjugation with different N-unsubstituted isatin moieties to furnish the target conjugates. As planned, the adopted strategy achieved a substantial improvement in the growth inhibitory profile for the target conjugates in comparison to the reported lead VI. The best results were obtained with N-propylindole -5-methylisatin hybrid 8a which displayed broad spectrum anti-proliferative action with efficient sub-panel GI50 (MG-MID) range from 1.33 to 4.23 µM, and promising full-panel GI50 (MG-MID) equals 3.10 µM, at the NCI five-dose assay. Also, hybrid 8a was able to provoke cell cycle disturbance and apoptosis in breast T-47D cells as evidenced by the DNA flow cytometry and Annexin V-FITC/PI assays. Furthermore, hybrid 8a exhibited good inhibitory action against cell cycle regulator CDK2 protein kinase and the anti-apoptotic Bcl-2 protein (IC50= 0.85 ± 0.03 and 0.46 ± 0.02 µM, respectively). Interestingly, molecular docking for hybrid 8a in CDK2 and Bcl-2 active sites unveiled that N-propyl group is involved in significant hydrophobic interactions. Taken together, the results suggested conjugate 8a as a promising lead for further development and optimisation as an efficient antitumor drug.

Antitumor properties of certain spirooxindoles towards hepatocellular carcinoma endowed with antioxidant activity

In the current medical era, spirooxindole motif stands out as a privileged heterospirocyclic scaffold that represents the core for a wide range of bioactive naturally isolated products (such as Strychnofoline and spirotryprostatins A and B) and synthetic compounds. Interestingly, no much attention has been paid to develop spirooxindole derivatives with dual antioxidant and anticancer activities. In this context, a series of spirooxindoles 6a-p was examined for their anticancer effect towards HepG2 hepatocellular carcinoma and PC-3 prostate cancer cell lines. Spirooxindole 6a was found to be an efficient anti-proliferative agent towards both HepG2 and PC-3 cells (IC50 = 6.9 and 11.8 µM, respectively). Afterwards, spirooxindole 6a was assessed for its apoptosis induction potential in HepG2 cells, where its pro-apoptotic impact was approved via the significant elevation in the Bax/Bcl-2 ratio and the expression levels of caspase-3.

Novel benzofuran-based sulphonamides as selective carbonic anhydrases IX and XII inhibitors: synthesis and in vitro biological evaluation

Pursuing on our efforts toward searching for efficient hCA IX and hCA XII inhibitors, herein we report the design and synthesis of new sets of benzofuran-based sulphonamides (4a,b, 5a,b, 9a-c, and 10a-d), featuring the zinc anchoring benzenesulfonamide moiety linked to a benzofuran tail via a hydrazine or hydrazide linker. All the target benzofurans were examined for their inhibitory activities toward isoforms hCA I, II, IX, and XII. The target tumour-associated hCA IX and XII isoforms were efficiently inhibited with KIs spanning in ranges 10.0-97.5 and 10.1-71.8 nM, respectively. Interestingly, arylsulfonehydrazones 9 displayed the best selectivity toward hCA IX and XII over hCA I (SIs: 39.4-250.3 and 26.0-149.9, respectively), and over hCA II (SIs: 19.6-57.1 and 13.0-34.2, respectively). Furthermore, the target benzofurans were assessed for their anti-proliferative activity, according to US-NCI protocol, toward a panel of sixty cancer cell lines. Only benzofurans 5b and 10b possessed selective and moderate growth inhibitory activity toward certain cancer cell lines.

Recent Advances in the Discovery of Multitargeted Tyrosine Kinase Inhibitors as Anticancer Agents

The treatment of cancer has been one of the most significant challenges for the medical field. Further research on the signal transduction pathway of tumor cells is driving the rapid development of antitumor agents targeting tyrosine kinases. However, most of the currently approved tyrosine kinase inhibitors based on the "single target/single drug" design are becoming less and less effective in the treatment of complex, heterogeneous, and multigenic cancers; this also results in resistance to chemotherapy. In contrast, multitargeted tyrosine kinase inhibitors (MT-TKIs) can effectively block multiple pathways of intracellular signal transduction. Therefore, they have therapeutic advantages over single-targeted inhibitors and have become a hotspot in antitumor drug research in recent years. This minireview summarizes recent advances in the discovery of MT-TKIs based on their chemical structures. In particular, we describe the kinase inhibitory and antitumor activity of promising compounds, as well as their structure - activity relationships (SARs).

Design, synthesis, and anti-proliferative evaluation of new quinazolin-4(3H)-ones as potential VEGFR-2 inhibitors

Inhibiting VEGFR-2 has been set up as a therapeutic strategy for treatment of cancer. Thus, nineteen new quinazoline-4(3H)-one derivatives were designed and synthesized. Preliminary cytotoxicity studies of the synthesized compounds were evaluated against three human cancer cell lines (HepG-2, MCF-7 and HCT-116) using MTT assay method. Doxorubicin and sorafenib were used as positive controls. Five compounds were found to have promising cytotoxic activities against all cell lines. Compound 16_f, containing a 2-chloro-5-nitrophenyl group, has emerged as the most active member. It was approximately 4.39-, 5.73- and 1.96-fold more active than doxorubicin and 3.88-, 5.59- and 1.84-fold more active than sorafenib against HepG2, HCT-116 and MCF-7 cells, respectively. The most active cytotoxic agents were further evaluated in vitro for their VEGFR-2 inhibitory activities. The results of in vitro VEGFR-2 inhibition were consistent with that of the cytotoxicity data. Molecular docking of these compounds into the kinase domain, moreover, supported the results.

Novel 2-indolinone thiazole hybrids as sunitinib analogues: Design, synthesis, and potent VEGFR-2 inhibition with potential anti-renal cancer activity

Novel 2-indolinone thiazole hybrids were designed and synthesized as VEGFR-2 inhibitors based on sunitinib, an FDA-approved anticancer drug. The proposed structures of the prepared 2-indolinone thiazole hybrids were confirmed based on their spectral data and CHN analyses. The target compounds were screened in vitro for their anti-VEGFR-2 activity. All tested compounds exhibited a potent submicromolar inhibition of VEGFR-2 kinase with IC₅₀ values ranging from 0.067 to 0.422 μM, relative to sunitinib reference drug (IC₅₀ = 0.075 ± 0.002 μM). Compounds 5, 15a, 15b, 17, 19c displayed excellent VEGFR-2 inhibitory activity, comparable or nearly equipotent to sunitinib. Compound 13b stood out as the most potent against VEGFR-2 showing IC₅₀ value of 0.067 ± 0.002 μM, lower than that of sunitinib. In addition, the most potent derivatives were assessed for their anticancer activity against two renal cancer cell lines. Compound 13b (IC₅₀ = 3.9 ± 0.13 μM) was more potent than sunitinib (IC₅₀ = 4.93 ± 0.16 μM) against CAKI-1 cell line. Moreover, thiazole 15b displayed excellent anticancer activity against CAKI-1 cell line (IC₅₀ = 3.31 ± 0.11 μM), superior to that of sunitinib (IC₅₀ = 4.93 ± 0.16 μM). Thiazole 15b was also equipotent to sunitinib (IC₅₀ = 1.23 ± 0.04 μM) against A498 cell line. Besides, compound 15b revealed a safety profile much better than that of sunitinib against normal human renal cells. Furthermore, a docking study revealed a proper fitting of the most active compounds into the ATP binding site of VEGFR-2, rationalizing their potent anti-VEGFR-2 activity.

Dual Targeting of VEGFR2 and C-Met Kinases via the Design and Synthesis of Substituted 3-(Triazolo-thiadiazin-3-yl)indolin-2-one Derivatives as Angiogenesis Inhibitors

The vascular endothelial growth factor receptor 2 (VEGFR2) and c-mesenchymal epithelial transition factor (c-Met) are members of receptor tyrosine kinases which have a crucial role in the process of angiogenesis. Isatin moiety is a versatile group that is shared in many compounds targeting both c-Met and VEGFR2 kinases. In this study, we designed and synthesized different derivatives of substituted 3-(triazolo-thiadiazin-3-yl)indolin-2-one derivatives (6a-y) as dual inhibitors for c-Met and VEGFR2 enzymes. Eight compounds 6a, 6b, 6e, 6l, 6n, 6r, 6v, and 6y were assessed for their anticancer activities against a panel of 58 cancer cell lines according to the US-NCI protocol. Compound 6b revealed the most effective antiproliferative potency (GI %), with broad-spectrum activity against different subpanels of the most NCI 58 tumor cell lines. An in vivo hen's egg-chorioallantoic membrane (HET-CAM) angiogenic study was carried out for 21 compounds 6a, b, d, f, h, i, k-o, t, and 6x to check their mortality and toxicity. At 100 μM concentration, all compounds produced 100% mortality of the chick embryos. At 40 μM concentration, 13 compounds did not exhibit any detectable mortality (nontoxic) and revealed a potent antiangiogenic effect. Seven compounds 6b, 6d, 6f, 6n, 6o, 6t, and 6x significantly decreased the number of blood vessels, and compound 6b was the most effective antiangiogenic agent comparable to dexamethasone. Molecular docking studies were conducted for compound 6b to investigate its mode of interaction within the binding site of both c-Met and VEGFR2 kinases.

Synthesis and in vitro anti-bladder cancer activity evaluation of quinazolinyl-arylurea derivatives

Based on the structural modification of molecular-targeted agent sorafenib, a series of quinazolinyl-arylurea derivatives were synthesized and evaluated for their anti-proliferative activities against six human cancer cell lines. Compared with other cell lines tested, T24 was more sensitive to most compounds. Compound 7j exhibited the best profile with lower IC₅₀ value and favorable selectivity. In this study, we focused on 7j-induced death forms of T24 cells and tried to elucidate the reason for its potent proliferative inhibitory activity. Compound 7j treatment could trigger three different cell death forms including apoptosis, ferroptosis, and autophagy; which form would occur depended on the concentrations and incubation time of 7j: (1) Lower concentrations within the initial 8 h of 7j treatment led to apoptosis-dependent death. (2) Ferroptosis and autophagy occurred in the case of higher concentrations combining with extended incubation time through effectively regulating the Sxc^-/GPx4/ROS and PI3K/Akt/mTOR/ULK1 pathways, respectively. (3) The above death forms were closely associated with intracellular ROS generation and decreased mitochondrial membrane potential induced by 7j. In molecular docking and structure-activity relationship analyses, 7j could bind well to the active site of the corresponding receptor glutathione peroxidase 4 (GPx4). Compound 7j could be a promising lead for molecular-targeted anti-bladder cancer agents' discovery.

Modulation of endoplasmic reticulum stress response in gut-origin encephalopathy: Impact of vascular endothelial growth factor receptor-2 manipulation

BACKGROUND

Septic encephalopathy, the most frequent complication of sepsis, is orchestrated by a complex interplay of signals that leads to high mortality rates among intensive care unit patients. However, the role of the vascular endothelial growth factor receptor-2 (VEGFR2) in endoplasmic reticulum stress response (ERSR), during septic encephalopathy, is still elusive.

AIM

This study was aimed to examine the effect of an in-house designed/synthesized VEGFR2 antagonist, named WAG4S, on septic encephalopathy using cecal ligation and perforation (CLP).

MAIN METHODS

Rats were intraperitoneally injected with WAG-4S (1 mg/kg/d) for 7 days post-CLP.

KEY FINDINGS

In septic animals, VEGFR2 antagonism declined the expression of cortical p-VEGFR2 and p-mammalian target of rapamycin complex-1 (p-mTORC1). It also worsened the behavioral and histopathological alterations beyond CLP. However, and contrary to CLP, WAG-4S decreased the p-protein kinase R-like ER kinase (p-PERK) and eukaryotic initiation factor-2α (p-eIF2α) expression. Moreover, VEGFR2 blockade upregulated the mRNA expression of activating transcription factor-4 (ATF4), binding immunoglobulin protein/glucose-regulated protein-78 (Bip/GRP78), growth arrest and DNA damage-34 (GADD34) and spliced X-box binding protein-1 (XBP1s) above CLP. Similarly, it boosted inositol requiring enzyme-1α (IRE1α) activation and redox imbalance. In the same context, WAG-4S augmented the protein levels of CLP-induced ERSR apoptotic markers, namely C/EBP homologous protein (CHOP/GADD153), c-jun N-terminal kinase (JNK) and caspase-3.

SIGNIFICANCE

In conclusion, the PERK/eIF2α axis inhibition, during septic encephalopathy, is VEGFR2-independent, whereas the activated IRE1α/XBP1s/CHOP/JNK/caspase-3 cue promotes the ERSR execution module through VEGFR2 inhibition. This has turned VEGFR2 into a potential therapeutic target for ameliorating such an ailment.

Synthesis, Biological Evaluation and In Silico Studies of Certain Oxindole-Indole Conjugates as Anticancer CDK Inhibitors

On account of their overexpression in a wide range of human malignancies, cyclin-dependent kinases (CDKs) are among the most validated cancer targets, and their inhibition has been featured as a valuable strategy for anticancer drug discovery. In this study, a hybrid pharmacophore approach was adopted to develop two series of oxindole-indole conjugates (6a-i and 9a-f) and carbocycle-indole conjugates (11a,b) as efficient antitumor agents with potential inhibitory action toward CDK4. All oxindole-indole conjugates, except 6i, 9b, and 9c efficiently affected the growth of the human breast cancer MCF-7 (IC₅₀: 0.39 ± 0.05-21.40 ± 1.58 μM) and/or MDA-MB-231 (IC₅₀: 1.03 ± 0.04-22.54 ± 1.67 μM) cell lines, whereas bioisosteric replacement of the oxindole nucleus with indane or tetralin rings (compounds 11a,b) diminished the anti-proliferative activity. In addition, hybrids 6e and 6f displayed effective cell cycle disturbance and proapoptotic capabilities in MCF-7 cells. Furthermore, the efficient anti-proliferative agents towards MCF-7 and/or MDA-MB-231 cell lines (6a-h, 9a, and 9e) were investigated for their potential inhibitory action toward CDK4. Hybrids 6a and 6e displayed good CDK4 inhibitory activity with IC₅₀s equal 1.82 and 1.26 µM, respectively. The molecular docking study revealed that oxindole moiety is implicated in two H-bonding interactions via both (NH) and (C=O) groups with the key amino acids Glu94 and Val96, respectively, whereas the indole framework is stably accommodated in a hydrophobic sub-pocket establishing hydrophobic interactions with the amino acid residues of Ile12, Val20, and Gln98 lining this sub-pocket. Collectively, these results highlighted hybrids 6a and 6e as good leads for further optimization as promising antitumor drugs toward breast malignancy and CDK inhibitors.

Sulfonamide-based 4-anilinoquinoline derivatives as novel dual Aurora kinase (AURKA/B) inhibitors: Synthesis, biological evaluation and in silico insights

Aurora kinases (AURKs) were identified as promising druggable targets for targeted cancer therapy. Aiming at the development of novel chemotype of dual AURKA/B inhibitors, herein we report the design and synthesis of three series of 4-anilinoquinoline derivatives bearing a sulfonamide moiety (5a-d, 9a-d and 11a-d). The % inhibition of AURKA/B was determined for all target quinolines, then compounds showed more than 50% inhibition on either of the enzymes, were evaluated further for their IC₅₀ on the corresponding enzyme. In particular, compound 9d displayed potent AURKA/B inhibitory activities with IC₅₀ of 0.93 and 0.09 µM, respectively. Also, 9d emerged as the most efficient anti-proliferative analogue in the US-NCI anticancer assay toward the NCI 60 cell lines panel, with broad spectrum activity against different cell lines from diverse cancer subpanels. Docking studies, confirmed that, the sulfonamide SO₂ oxygen was involved in a hydrogen bond with Lys162 and Lys122 in AURKA and AURKB, respectively, whereas, the sulfonamide NH could catch hydrogen bond interaction with the surrounding amino acid residues Lys141, Glu260, and Asn261 in AURKA and Lys101, Glu177, and Asp234 in AURKB. Furthermore, N1 nitrogen of the quinoline scaffold formed an essential hydrogen bond with the hinge region key amino acids Ala213 and Ala173 in AURKA and AURKB, respectively.

Almehizia A, Al-Ansary GH. Marine-Inspired Bis-indoles Possessing Antiproliferative Activity against Breast Cancer; Design, Synthesis, and Biological Evaluation

Diverse indoles and bis-indoles extracted from marine sources have been identified as promising anticancer leads. Herein, we designed and synthesized novel bis-indole series 7a-f and 9a-h as Topsentin and Nortopsentin analogs. Our design is based on replacing the heterocyclic spacer in the natural leads by a more flexible hydrazide linker while sparing the two peripheral indole rings. All the synthesized bis-indoles were examined for their antiproliferative action against human breast cancer (MCF-7 and MDA-MB-231) cell lines. The most potent congeners 7e and 9a against MCF-7 cells (IC50 = 0.44 ± 0.01 and 1.28 ± 0.04 μM, respectively) induced apoptosis in MCF-7 cells (23.7-, and 16.8-fold increase in the total apoptosis percentage) as evident by the externalization of plasma membrane phosphatidylserine detected by Annexin V-FITC/PI assay. This evidence was supported by the Bax/Bcl-2 ratio augmentation (18.65- and 11.1-fold compared to control) with a concomitant increase in the level of caspase-3 (11.7- and 9.5-fold) and p53 (15.4- and 11.75-fold). Both compounds arrested the cell cycle mainly in the G2/M phase. Furthermore, 7e and 9a displayed good selectivity toward tumor cells (S.I. = 38.7 and 18.3), upon testing of their cytotoxicity toward non-tumorigenic breast MCF-10A cells. Finally, compounds 7a, 7b, 7d, 7e, and 9a were examined for their plausible CDK2 inhibitory action. The obtained results (% inhibition range: 16%-58%) unveiled incompetence of the target bis-indoles to inhibit CDK2 significantly. Collectively, these results suggested that herein reported bis-indoles are good lead compounds for further optimization and development as potential efficient anti-breast cancer drugs.

Design, synthesis, and molecular docking of novel 2-arylbenzothiazole multiangiokinase inhibitors targeting breast cancer

A novel series of 2-arylbenzothiazoles 9, 10, and 12 were designed and synthesized as VEGFR-2/FGFR-1/PDGFR-β multiangiokinase inhibitors targeting breast cancer. Structural elongation of the known 2-phenylbenzothiazole scaffold (type I protein kinase inhibitor [PKI]), was carried out to afford series of type II PKIs 9, 10, and 12. Compounds 9d, 9f, 9i, and 9k exhibited potent multikinase inhibitory activity with IC₅₀ values of 0.19, 0.18, 0.17, and 0.13 μM, respectively, against VEGFR-2; IC₅₀ values of 0.28, 0.37, 0.19, and 0.27 μM, respectively, against FGFR-1; and IC₅₀ values of 0.07, 0.04, 0.08, and 0.14 μM, respectively, against PDGFR-β. Moreover, the synthesized benzothiazoles demonstrated promising cytotoxic activity against the MCF-7 cell line. The most potent benzothiazoles 9d and 9i exhibited IC₅₀ values of 7.83 and 6.58 μM, respectively, on the MCF-7 cell line in comparison to sorafenib (III), which showed IC₅₀  = 4.33 μM. Additionally, 9d and 9i showed VEGFR-2 inhibitory activity in MCF-7 cells of 81% and 83% when compared with sorafenib (III), which showed 88% inhibition. Molecular docking of the designed compounds in the VEGFR-2 and FGFR-1 active sites showed the accommodation of the 2-phenylbenzothiazole moiety, as reported, in the hinge region of the receptor tyrosine kinase (RTK)-binding site, while the amide moiety is involved in hydrogen bond interactions with the key amino acids in the gate area; this in turn directs the aryl group to the hydrophobic allosteric back pocket of the RTKs in a type II-like binding mode. The synthesized benzothiazoles showed satisfactory ADME properties for further optimization in drug discovery.

Targeting Receptor Tyrosine Kinase VEGFR-2 in Hepatocellular Cancer: Rational Design, Synthesis and Biological Evaluation of 1,2-Disubstituted Benzimidazoles

In this study, a novel series of 1,2-disubstituted benzo[d]imidazoles was rationally designed as VEGFR-2 inhibitors targeting hepatocellular carcinoma. Our design strategy is two-fold; it aimed first at studying the effect of replacing the 5-methylfuryl moiety of the well-known antiangiogenic 2-furylbenzimidazoles with an isopropyl moiety on the VEGFR-2 inhibitory activity and the cytotoxic activity. Our second objective was to further optimize the structures of the benzimidazole derivatives through elongation of the side chains at their one-position for the design of more potent type II-like VEGFR-2 inhibitors. The designed 1,2-disubstituted benzimidazoles demonstrated potent cytotoxic activity against the HepG2 cell line, reaching IC₅₀ = 1.98 μM in comparison to sorafenib (IC₅₀ = 10.99 μM). In addition, the synthesized compounds revealed promising VEGFR-2 inhibitory activity in the HepG2 cell line, e.g., compounds 17a and 6 showed 82% and 80% inhibition, respectively, in comparison to sorafenib (% inhibition = 92%). Studying the effect of 17a on the HepG2 cell cycle demonstrated that 17a arrested the cell cycle at the G2/M phase and induced a dose-dependent apoptotic effect. Molecular docking studies of the synthesized 1,2-disubstituted benzimidazoles in the VEGFR-2 active site displayed their ability to accomplish the essential hydrogen bonding and hydrophobic interactions for optimum inhibitory activity.

Synthesis, biological evaluation and in silico studies with 4-benzylidene-2-phenyl-5(4H)-imidazolone-based benzenesulfonamides as novel selective carbonic anhydrase IX inhibitors endowed with anticancer activity

In the presented work, we report the synthesis of a series of 4-benzylidene-2-phenyl-5(4H)-imidazolone-based benzenesulfonamides 7a-fvia the Erlenmeyer-Plöchl reaction. All the prepared imidazolones 7a-f were evaluated as inhibitors of human (h) carbonic anhydrases (CA, EC 4.2.1.1) cytosolic isoforms hCA I and II, as well as transmembrane tumor-associated isoforms hCA IX and XII. All the tested hCA isoforms were inhibited by the prepared imidazolones 7a-f in variable degrees with the following KIs ranges: 673.2-8169 nM for hCA I, 61.2-592.1 nM for hCA II, 23-155.4 nM for hCA XI, and 21.8-179.6 nM for hCA XII. In particular, imidazolones 7a, 7e, and 7f exhibited good selectivity towards the tumor-associated isoforms (CAs IX and XII) over the off-target cytosolic (CAs I and II) with selectivity index (SI) in the range of 6.2-19.4 and 3.3-8, respectively. Moreover, imidazolones 7a-f were screened for their anticancer activity in one dose (10-5 M) assay against a panel of 60 cancer cell lines according to US-NCI protocol. Furthermore, 7a, 7e and 7f were evaluated for their anti-proliferative activity against colorectal cancer HCT-116 and breast cancer MCF-7 cell lines. Furthermore, 7e and 7f were screened for cell cycle disturbance and apoptosis induction in HCT-116 cells. Finally, a molecular docking study was carried out to rationalize the obtained results.