Design, synthesis, and anticancer evaluation of N-sulfonylpiperidines as potential VEGFR-2 inhibitors, apoptotic inducers

A new panel of N-sulfonylpiperidine derivatives has been designed and synthesized as vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitors. Anti-proliferative activities of the synthesized members were tested against colorectal carcinoma (HCT-116), hepatocellular carcinoma (HepG-2), and breast cancer (MCF-7) cell lines. Compounds 3a, 4, 8, and 9 showed the highest activities against the tested cell lines. In particular, compound 8 showed excellent activities against HCT-116, HepG-2, and MCF-7 with IC50 values of 3.94, 3.76, and 4.43 μM, respectively. Such IC50 values are comparable to vinblastine (IC50 = 3.21, 7.35, 5.83 μM, respectively) and doxorubicin (IC50 = 6.74, 7.52, 8.19 μM, respectively). In vitro VEGFR-2 inhibitory activity of the most promising molecules (3a, 4, 8, and 9) indicated that compound 8 is the highest VEGFR-2 inhibitor with an IC50 of 0.0554 μM, compared to sorafenib (IC50 = 0.0416 μM). The most promising candidates (3a, 4, 8, and 9) were subjected to flow cytometry analyses to assess their effects on the cell cycle behavior and the apoptotic power against the three tested cell lines (HCT-116, HepG-2, and MCF-7). The tested compound arrested the tumor cells at both the G2/M and Pre-G1 phases. In addition, compound 9 was proved as the most effective apoptotic inducer among the tested compounds against the tested cells. Molecular docking studies against VEGFR-2 (PDB ID: 2OH4) revealed good binding modes of the synthesized compound similar to that of sorafenib. Computational investigation of ADMET parameters revealed the drug-likeness of the synthesized compounds.

Synthesis of Bis-thiazoles Tethered 1,4-Dihydropyridine and Pyridine Linkers via Simple Oxidation and their Molecular Docking as VEGFR -TK Inhibitors

AIM

In this study, a neoteric and expedient oxidation method is applied for a variety of Hantzsch 1,4-dihydropyridine derivatives such as 1,4-dihydro- 2,6-dimethyl-3,5-diacetylpyridine, 3,5-bis-hydrazono--2,6-dimethyl-1,4-dihydropyridine, and 3,5-bis-thiazoly-2,6-dimethyl-1,4-dihydro pyridine.

METHOD

This simple oxidation is based upon the in situ generation of nitrous acid from an aqueous sodium nitrite and acetic acid mixture and could be used to downgrade costs, sustain resources, and minimize chemical wastes. Also, a molecular modeling strategy was used to study the mechanism of action for various derivatives of bis-hydrazinylidene- thiazole as the protein Vascular Endothelial Growth Factor Receptor Tyrosine Kinase (VEGFR TK) inhibitor through evaluating their binding scores and modes compared with Sorafenib as a reference standard.

RESULT

The results revealed that the interaction of hydrazinylidene and thiazole as an anticancer Tyrosine Kinase inhibitor has been improved.

CONCLUSION

Additionally, the compounds exhibiting the highest activity were assessed for their potential anticancer effects against HepG-2, MCF-7, and WI-38 cells, and the outcomes demonstrated encouraging activity against cancer.

Discovery of new thiazolidine-2,4-dione derivatives as potential VEGFR-2 inhibitors: In vitro and in silico studies

In this study, a series of seven novel 2,4-dioxothiazolidine derivatives with potential anticancer and VEGFR-2 inhibiting abilities were designed and synthesized as VEGFR-2 inhibitors. The synthesized compounds were tested in vitro for their potential to inhibit VEGFR-2 and the growth of HepG2 and MCF-7 cancer cell lines. Among the compounds tested, compound 22 (IC50 = 0.079 μM) demonstrated the highest anti-VEGFR-2 efficacy. Furthermore, it demonstrated significant anti-proliferative activities against HepG2 (IC50 = 2.04 ± 0.06 μM) and MCF-7 (IC50 = 1.21 ± 0.04 M). Additionally, compound 22 also increased the total apoptotic rate of the MCF-7 cancer cell lines with cell cycle arrest at S phase. As well, computational methods were applied to study the VEGFR-2-22 complex at the molecular level. Molecular docking and molecular dynamics (MD) simulations were used to investigate the complex's structural and kinetic characteristics. The DFT calculations further revealed the structural and electronic properties of compound 22. Finally, computational ADMET and toxicity tests were performed indicating the likeness of the proposed compounds to be drugs. The results suggest that compound 22 displays promise as an effective anticancer treatment and can serve as a model for future structural modifications and biological investigations in this field.

Discovery of sulfonamide-tethered isatin derivatives as novel anticancer agents and VEGFR-2 inhibitors

In this work, new isatin-based sulphonamides (6a-i, 11a-c, 12a-c) were designed and synthesised as potential dual VEGFR-2 and carbonic anhydrase inhibitors with anticancer activities. Firstly, all target isatins were examined for in vitro antitumor action on NCI-USA panel (58 tumour cell lines). Then, the most potent derivatives were examined for the potential CA inhibitory action towards the physiologically relevant hCA isoforms I, II, and tumour-linked hCA IX isoform, in addition, the VEGFR-2 inhibitory activity was evaluated. The target sulphonamides failed to inhibit the CA isoforms that could be attributable to the steric effect of the neighbouring methoxy group, whereas they displayed potent VEGFR-2 inhibitory effect. Following that, isatins 11b and 12b were tested for their influence on the cell cycle disturbance, and towards the apoptotic potential. Finally, detailed molecular modelling analyses, including docking and molecular dynamics, were carried out to assess the binding mode and stability of target isatins.

Computer-assisted drug discovery (CADD) of an anti-cancer derivative of the theobromine alkaloid inhibiting VEGFR-2

VEGFR-2 is a significant target in cancer treatment, inhibiting angiogenesis and impeding tumor growth. Utilizing the essential pharmacophoric structural properties, a new semi-synthetic theobromine analogue (T-1-MBHEPA) was designed as VEGFR-2 inhibitor. Firstly, T-1-MBHEPA's stability and reactivity were indicated through several DFT computations. Additionally, molecular docking, MD simulations, MM-GPSA, PLIP, and essential dynamics (ED) experiments suggested T-1-MBHEPA's strong binding capabilities to VEGFR-2. Its computational ADMET profiles were also studied before the semi-synthesis and indicated a good degree of drug-likeness. T-1-MBHEPA was then semi-synthesized to evaluate the design and the in silico findings. It was found that, T-1-MBHEPA inhibited VEGFR-2 with an IC50 value of 0.121 ± 0.051 µM, as compared to sorafenib which had an IC50 value of 0.056 µM. Similarly, T-1-MBHEPA inhibited the proliferation of HepG2 and MCF7 cell lines with IC50 values of 4.61 and 4.85 µg/mL respectively - comparing sorafenib's IC50 values which were 2.24 µg/mL and 3.17 µg/mL respectively. Interestingly, T-1-MBHEPA revealed a noteworthy IC50 value of 80.0 µM against the normal cell lines exhibiting exceptionally high selectivity indexes (SI) of 17.4 and 16. 5 against the examined cell lines, respectively. T-1-MBHEPA increased the percentage of apoptotic MCF7 cells in early and late stages, respectively, from 0.71 % to 7.22 % and from 0.13 % to 2.72 %, while the necrosis percentage was increased to 11.41 %, in comparison to 2.22 % in control cells. Furthermore, T-1-MBHEPA reduced the production of pro-inflammatory cytokines TNF-α and IL-2 in the treated MCF7 cells by 33 % and 58 %, respectively indicating an additional anti-angiogenic mechanism. Also, T-1-MBHEPA decreased significantly the potentialities of MCF7 cells to heal and migrate from 65.9 % to 7.4 %. Finally, T-1-MBHEPA's oral treatment didn't show toxicity on the liver function (ALT and AST) and the kidney function (creatinine and urea) levels of mice.

Discovery of indolinone-bearing benzenesulfonamides as new dual carbonic anhydrase and VEGFR-2 inhibitors possessing anticancer and pro-apoptotic properties

In the current medical era, the utilization of a single small molecule to simultaneously target two distinct molecular targets is emerging as a highly effective strategy in the battle against cancer. Carbonic Anhydrase (CA) and Vascular-Endothelial Growth Factor (VEGF) are genes that are activated in response to low oxygen levels (hypoxia) and play a role in the development and progression of tumors in hypoxic conditions. Herein we report the design, synthesis, and biological assessment of a series of novel indolinone-based benzenesulfonamides (8a-k, 11a-d, 15a-d, and 16) as potential dual inhibitors for cancer-associated hCA IX/XII and VEGFR-2. All the synthesized sulfonamides were assessed for their inhibitory effect against four CA isoforms I, II, IX, and XII where they displayed varying degrees of hCA inhibition. The most effective and selective hCA IX and XII inhibitors 8g, 8j and 15b were chosen to be tested for their in vitro inhibitory impact against VEGFR-2 as well as their antiproliferative impact against VEGFR-2 overexpressing MDA-MB-231 and MCF-7 breast cancer cells. Furthermore, molecular docking studies were conducted within the hCA IX, XII, and VEGFR-2 active sites to explain the observed inhibitory results.

Anti-breast cancer potential of a new xanthine derivative: In silico, antiproliferative, selectivity, VEGFR-2 inhibition, apoptosis induction and migration inhibition studies

BACKGROUND

The overexpression of VEGFR-2 receptors in breast cancer provides a valuable approach to anticancer strategies. Targeting VEGFR-2, a new semisynthetic compound (T-1-MCPAB) has been designed.

METHODS

Computational methods (ADMET, toxicity, DFT, Molecular Docking, Molecular Dynamics Simulations, MM-GBSA, PLIP, and PCAT) were conducted. In addition to the semi-synthesis, in vitro studies (anti-VEGFR-2, anti-proliferative, flow cytometry, and wound scratch assay) were employed.

RESULTS

ADME and toxicity profiles of T-1-MCPAB studies indicated its overall drug-likeness showing results much better than Sorafenib. Then, T-1-MCPAB's exact 3D structure, stability, and reactivity were evoked by the DFT calculations. Molecular docking, molecular dynamics simulations, MM-GPSA, PLIP, and PCAT studies denoted the correct binding and inhibiting potential of T-1-MCPAB, towards VEGFR-2 protein. After the semisynthesis, T-1-MCPAB inhibited VEGFR-2 with an IC50 of 0.135 µM, which was comparable to sorafenib's IC50 of 0.0591 µM. T-1-MCPAB also showed a notable performance against MCF7 and T47D breast cancer cell lines with IC50 values of 30.95 µM and 63.64 µM, respectively, and had high selectivity index values of 3.7 and 1.8, respectively. Furthermore, T-1-MCPAB influenced early and late apoptosis and significantly decreased the potential of MCF7 cells to heal and migrate.

CONCLUSION

T-1-MCPAB is a promising VEGFR-2 inhibitor with potential for breast cancer treatment. Further chemical and biological studies are needed to explore its potential as a therapeutic agent.

Natural products targeting tumour angiogenesis

Tumour angiogenesis is the formation of new blood vessels to support the growth of a tumour. This process is critical for tumour progression and metastasis, making it an attractive approach to cancer therapy. Natural products derived from plants, animals or microorganisms exert anti-angiogenic properties and can be used to inhibit tumour growth and progression. In this review, we comprehensively report on the current status of natural products against tumour angiogenesis from four perspectives until March 2023: (1) the role of pro-angiogenic factors and antiangiogenic factors in tumour angiogenesis; (2) the development of anti-tumour angiogenesis therapy (monoclonal antibodies, VEGFR-targeted small molecules and fusion proteins); (3) the summary of anti-angiogenic natural agents, including polyphenols, polysaccharides, alkaloids, terpenoids, saponins and their mechanisms of action, and (4) the future perspectives of anti-angiogenic natural products (bioavailability improvement, testing of dosage and side effects, combination use and discovery of unique natural-based compounds). Our review aims to better understand the potential of natural products for drug development in inhibiting tumour angiogenesis and further aid the effective transition of these outcomes into clinical trials.

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.

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 thiazolidine-2,4-diones hybrids with 1,2-dihydroquinolones and 2-oxindoles as potential VEGFR-2 inhibitors: in-vitro anticancer evaluation and in-silico studies

A thiazolidine-2,4-dione nucleus was molecularly hybridised with the effective antitumor moieties; 2-oxo-1,2-dihydroquinoline and 2-oxoindoline to obtain new hybrids with potential activity against VEGFR-2. The cytotoxic effects of the synthesised derivatives against Caco-2, HepG-2, and MDA-MB-231 cell lines were investigated. Compound 12a was found to be the most potent candidate against the investigated cell lines with IC₅₀ values of 2, 10, and 40 µM, respectively. Furthermore, the synthesised derivatives were tested in vitro for their VEGFR-2 inhibitory activity showing strong inhibition. Moreover, an in vitro viability study against Vero non-cancerous cell line was investigated and the results reflected a high safety profile of all tested compounds. Compound 12a was further investigated for its apoptotic behaviour by assessing the gene expression of four genes (Bcl2, Bcl-xl, TGF, and Survivin). Molecular dynamic simulations authenticated the high affinity, accurate binding, and perfect dynamics of compound 12a against VEGFR-2.

Discovery of novel thiazolyl-pyrazolines as dual EGFR and VEGFR-2 inhibitors endowed with in vitro antitumor activity towards non-small lung cancer

New series of thiazolyl-pyrazoline derivatives (7a–7d, 10a–10d and 13a–13f) have been synthesised and assessed for their potential EGFR and VEGFR-2 inhibitory activities. Compounds 10b and 10d exerted potent and selective inhibitory activity towards the two receptor tyrosine kinases; EGFR (IC₅₀ = 40.7 ± 1.0 and 32.5 ± 2.2 nM, respectively) and VEGFR-2 (IC₅₀ = 78.4 ± 1.5 and 43.0 ± 2.4 nM, respectively). The best anti-proliferative activity for the examined thiazolyl-pyrazolines was observed against the non-small lung cancer cells (NSCLC). Compounds 10b and 10d displayed pronounced efficacy against A549 (IC₅₀ = 4.2 and 2.9 µM, respectively) and H441 cell lines (IC₅₀ = 4.8 and 3.8 µM, respectively). Moreover, our results indicated that 10b and 10d were much more effective towards EGFR-mutated NSCLC cell lines (NCI-H1650 and NCI-H1975 cells) than gefitinib. Finally, compounds 10b and 10d induce G2/M cell cycle arrest and apoptosis and inhibit migration in A549 cancerous cells.

New benzoxazole derivatives as potential VEGFR-2 inhibitors and apoptosis inducers: design, synthesis, anti-proliferative evaluation, flowcytometric analysis, and in silico studies

A new series of benzoxazole derivatives were designed and synthesised to have the main essential pharmacophoric features of VEGFR-2 inhibitors. Cytotoxic activities were evaluated for all derivatives against two human cancer cell lines, MCF-7 and HepG2. Also, the effect of the most cytotoxic derivatives on VEGFR-2 protein concentration was assessed by ELISA. Compounds 14o, 14l, and 14b showed the highest activities with VEGFR-2 protein concentrations of 586.3, 636.2, and 705.7 pg/ml, respectively. Additionally, the anti-angiogenic property of compound 14b against human umbilical vascular endothelial cell (HUVEC) was performed using a wound healing migration assay. Compound 14b reduced proliferation and migratory potential of HUVEC cells. Furthermore, compound 14b was subjected to further biological investigations including cell cycle and apoptosis analyses. Compound 14b arrested the HepG2 cell growth at the Pre-G1 phase and induced apoptosis by 16.52%, compared to 0.67% in the control (HepG2) cells. The effect of apoptosis was buttressed by a 4.8-fold increase in caspase-3 level compared to the control cells. Besides, different in silico docking studies were also performed to get better insights into the possible binding mode of the target compounds with VEGFR-2 active sites.

1,3,4-Oxadiazole-naphthalene hybrids as potential VEGFR-2 inhibitors: design, synthesis, antiproliferative activity, apoptotic effect, and in silico studies

In the current work, some 1,3,4-oxadiazole-naphthalene hybrids were designed and synthesised as VEGFR-2 inhibitors. The synthesised compounds were evaluated in vitro for their antiproliferative activity against two human cancer cell lines namely, HepG-2 and MCF-7. Compounds that exhibited promising cytotoxicity (5, 8, 15, 16, 17, and 18) were further evaluated for their VEGFR-2 inhibitory activities. Compound 5 showed good antiproliferative activity against both cell lines and inhibitory effect on VEGFR-2. Besides, it induced apoptosis by 22.86% compared to 0.51% in the control (HepG2) cells. This apoptotic effect was supported by a 5.61-fold increase in the level of caspase-3 compared to the control cells. Moreover, it arrested the HepG2 cell growth mostly at the Pre-G1 phase. Several in silico studies were performed including docking, ADMET, and toxicity studies to predict binding mode against VEGFR-2 and to anticipate pharmacokinetic, drug-likeness, and toxicity of the synthesised compounds.

Design, Synthesis, Molecular Modeling, and Anticancer Evaluation of New VEGFR-2 Inhibitors Based on the Indolin-2-One Scaffold

A new series of indoline-2-one derivatives was designed and synthesized based on the essential pharmacophoric features of VEGFR-2 inhibitors. Anti-proliferative activities were assessed for all derivatives against breast (MCF-7) and liver (HepG2) cancer cell lines, using sunitinib as a reference agent. The most potent anti-proliferative derivatives were evaluated for their VEGFR-2 inhibition activity. The effects of the most potent inhibitor, 17a, on cell cycle, apoptosis, and expression of apoptotic markers (caspase-3&-9, BAX, and Bcl-2) were studied. Molecular modeling studies, such as docking simulations, physicochemical properties prediction, and pharmacokinetic profiling were performed. The results revealed that derivatives 5b, 10e, 10g, 15a, and 17a exhibited potent anticancer activities with IC50 values from 0.74-4.62 µM against MCF-7 cell line (sunitinib IC50 = 4.77 µM) and from 1.13-8.81 µM against HepG2 cell line (sunitinib IC50 = 2.23 µM). Furthermore, these compounds displayed potent VEGFR-2 inhibitory activities with IC50 values of 0.160, 0.358, 0.087, 0.180, and 0.078 µM, respectively (sunitinib IC50 = 0.139 µM). Cell cycle analysis demonstrated the ability of 17a to induce a cell cycle arrest of the HepG2 cells at the S phase and increase the total apoptosis by 3.5-fold. Moreover, 17a upregulated the expression levels of apoptotic markers caspase-3 and -9 by 6.9-fold and 3.7-fold, respectively. In addition, 17a increased the expression level of BAX by 2.7-fold while decreasing the expression level of Bcl-2 by 1.9-fold. The molecular docking simulations displayed enhanced binding interactions and similar placement as sunitinib inside the active pocket of VEGFR-2. The molecular modeling calculations showed that all the test compounds were in accordance with Lipinski and Veber rules for oral bioavailability and had promising drug-likeness behavior.

(E)-N-(3-(1-(2-(4-(2,2,2-Trifluoroacetamido)benzoyl)hydrazono)ethyl)phenyl)nicotinamide: A Novel Pyridine Derivative for Inhibiting Vascular Endothelial Growth Factor Receptor-2: Synthesis, Computational, and Anticancer Studies

(E)-N-(3-(1-(2-(4-(2,2,2-Trifluoroacetamido)benzoyl)hydrazono)ethyl)phenyl)nicotinamide (compound 10) was designed as an antiangiogenic VEGFR-2 inhibitor with the essential pharmacophoric structural properties to interact with the catalytic pocket of VEGFR-2. The designed derivative was synthesized, and its structure was confirmed through Ms, elemental, ¹H, and ¹³C spectral data. The potentiality of the designed pyridine derivative to bind with and inhibit the vascular endothelial growth factor receptor-2 (VEGFR-2) enzyme was indicated by molecular docking assessments. In addition, six molecular dynamic (MD) experiments proved its correct binding with VEGFR-2 over 100 ns. Additionally, the molecular mechanics energies, combined with the generalized born and surface area (MM-GBSA) analysis, identified the precise binding with optimum energy. To explore the stability and reactivity of the designed pyridine derivative, density functional theory (DFT) calculations, including electrostatic potential maps and total electron density, were carried out. Additionally, the absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis demonstrated its general likeness and its safety. The designed compound was synthesized to evaluate its effects against VEGFR-2 protein, cancer, and normal cells. The in vitro results were concordant with the in silico results, because the new pyridine derivative (compound 10) displayed VEGFR-2 inhibition with an IC₅₀ value of 65 nM and displayed potent cytotoxic properties against hepatic (HepG2) and breast (MCF-7) cancer cell lines with IC₅₀ values of 21.00 and 26.10 μM, respectively; additionally, it exhibited high selectivity indices against the normal cell lines (W-38) of 1.55 and 1.25, respectively. The obtained results present compound 10 as a new lead VEGFR-2 inhibitor for further biological investigation and chemical modifications.

New Oxazolo[5,4-d]pyrimidines as Potential Anticancer Agents: Their Design, Synthesis, and In Vitro Biological Activity Research

Cancer is a large group of diseases in which the rapid proliferation of abnormal cells generally leads to metastasis to surrounding tissues or more distant ones through the lymphatic and blood vessels, making it the second leading cause of death worldwide. The main challenge in designing a modern anticancer therapy is to develop selective compounds that exploit specific molecular targets. In this work, novel oxazolo[5,4-d]pyrimidine derivatives were designed, synthesized, and evaluated in vitro for their cytotoxic activity against a panel of four human cancer cell lines (lung carcinoma: A549, breast adenocarcinoma: MCF7, metastatic colon adenocarcinoma: LoVo, primary colon adenocarcinoma: HT29), along with their P-glycoprotein-inhibitory ability and pro-apoptotic activity. These oxazolo[5,4-d]pyrimidine derivatives, which are structurally similar to nucleic purine bases in general, are characterized by the presence of a pharmacologically favorable isoxazole substituent at position 2 and aliphatic amino chains at position 7 of the condensed heterocyclic system. In silico analysis of the obtained compounds identified their potent inhibitory activity towards human vascular endothelial growth factor receptor-2 (VEGFR-2). Molecular docking was performed to assess the binding mode of new derivatives to the VEGFR-2 active site. Then, their physicochemical, pharmacokinetic, and pharmacological properties (i.e., ADME-administration, distribution, metabolism, and excretion) were also predicted to assess their druglikeness. In particular, compound 3g (with a 3-(N,N-dimethylamino)propyl substituent) was found to be the most potent against the HT29 cell line, with a 50% cytotoxic concentration (CC₅₀) of 58.4 µM, exceeding the activity of fluorouracil (CC₅₀ = 381.2 μM) and equaling the activity of cisplatin (CC₅₀ = 47.2 µM), while being less toxic to healthy human cells (such as normal human dermal fibroblasts (NHDFs)) than these reference drugs. The results suggest that compound 3g is a potentially promising candidate for the treatment of primary colorectal cancer.

New application of novel tetrazine derivatives as potent VEGFR-2 kinase inhibitors and anti-cancer agents

Background: A novel series of s-tetrazine derivatives was designed as a new scaffold and synthesized efficiently as VEGFR-2 inhibitors for the first time. Methodology & results: The inhibitory activities of the new compounds were tested by MTT assay and enzyme assay, respectively. Western blot assay, cell apoptosis assay and cell migration assay were carried out to study the action mechanism of them. All the synthesized compounds showed evident VEGFR-2 inhibitory activities (IC₅₀ in the range of 88.53-257.55 nM). Compounds 23h, 25d, 26e and 27c showed excellent anti-proliferative activities against the four tested cell lines and were better than sorafenib basically. Conclusion: Compounds with good activities based on this novel scaffold can be screened successfully.

New [1,2,4]triazolo[4,3-c]quinazoline derivatives as vascular endothelial growth factor receptor-2 inhibitors and apoptosis inducers: Design, synthesis, docking, and antiproliferative evaluation

In continuation of our previous efforts in the field of design and synthesis of vascular endothelial growth factor receptor (VEGFR)-2 inhibitors, a new series of [1,2,4]triazolo[4,3-c]quinazoline derivatives were designed and synthesized as modified analogs of some reported VEGFR-2 inhibitors. The synthesized compounds were designed to have the essential pharmacophoric features of VEGFR-2 inhibitors. Antiproliferative activities of the synthesized compounds were investigated against two tumor cell lines (HepG2 and HCT-116) using sorafenib as a positive control. Compound 10k emerged as the most promising antiproliferative agent with IC₅₀ values of 4.88 and 5.21 µM against HepG2 and HCT-116 cells, respectively. Also, it showed the highest inhibitory activity against VEGFR-2 with an IC₅₀ value of 53.81 nM compared to sorafenib (IC₅₀  = 44.34 nM). Cell cycle analysis revealed that compound 10k can arrest HepG2 cells at both the S and G2/M phases. In addition, this compound produced a tenfold increase in apoptotic cells compared to the control. Furthermore, the effect of compound 10k on the expression level of BAX, Bcl-2, and caspase-3 was assessed. This compound caused a 3.35-fold increase in BAX expression levels and a 1.25-fold reduction in Bcl-2 expression levels. The BAX/Bcl-2 ratio was calculated to be 4.57, indicating a promising apoptotic effect. It also showed a significant increase in the level of caspase-3 (4.12-fold) compared to the control cells. In silico docking, absorption, distribution, metabolism, excretion, and toxicity, and toxicity studies were performed for the synthesized compounds to investigate their binding patterns against the proposed biological target (VEGFR-2) and to assess the drug-likeness characters.

Design, synthesis, molecular modeling and biological evaluation of novel Benzoxazole-Benzamide conjugates via a 2-Thioacetamido linker as potential anti-proliferative agents, VEGFR-2 inhibitors and apoptotic inducers

A novel series of 2-thioacetamide linked benzoxazole-benzamide conjugates 1-15 was designed as potential inhibitors of the vascular endothelial growth factor receptor-2 (VEGFR-2). The prepared compounds were evaluated for their potential antitumor activity and their corresponding selective cytotoxicity was estimated using normal human fibroblast (WI-38) cells. Compounds 1, 9-12 and 15 showed good selectivity and displayed excellent cytotoxic activity against both HCT-116 and MCF-7 cancer cell lines compared to sorafenib, used as a reference compound. Furthermore, compounds 1 and 11 showed potent VEGFR-2 inhibitory activity. The cell cycle progression assay showed that 1 and 11 induced cell cycle arrest at G2/M phase, with a concomitant increase in the pre-G1 cell population. Further pharmacological studies showed that 1 and 11 induced apoptosis and inhibited the expression of the anti-apoptotic Bcl-2 and Bcl-xL proteins in both cell lines. Therefore, compounds 1 and 11 might serve as promising candidates for future anticancer therapy development.

Discovery of new nicotinamides as apoptotic VEGFR-2 inhibitors: virtual screening, synthesis, anti-proliferative, immunomodulatory, ADMET, toxicity, and molecular dynamic simulation studies

A library of modified VEGFR-2 inhibitors was designed as VEGFR-2 inhibitors. Virtual screening was conducted for the hypothetical library using in silico docking, ADMET, and toxicity studies. Four compounds exhibited high in silico affinity against VEGFR-2 and an acceptable range of the drug-likeness. These compounds were synthesised and subjected to in vitro cytotoxicity assay against two cancer cell lines besides VEGFR-2 inhibitory determination. Compound D-1 showed cytotoxic activity against HCT-116 cells almost double that of sorafenib. Compounds A-1, C-6, and D-1 showed good IC₅₀ values against VEGFR-2. Compound D-1 markedly increased the levels of caspase-8 and BAX expression and decreased the anti-apoptotic Bcl-2 level. Additionally, compound D-1 caused cell cycle arrest at pre-G1 and G2-M phases in HCT-116 cells and induced apoptosis at both early and late apoptotic stages. Compound D-1 decreased the level of TNF-α and IL6 and inhibited TNF-α and IL6. MD simulations studies were performed over 100 ns.

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.

Discovery of new 3-methylquinoxalines as potential anti-cancer agents and apoptosis inducers targeting VEGFR-2: design, synthesis, and in silico studies

There is an urgent need to design new anticancer agents that can prevent cancer cell proliferation even with minimal side effects. Accordingly, two new series of 3-methylquinoxalin-2(1H)-one and 3-methylquinoxaline-2-thiol derivatives were designed to act as VEGFR-2 inhibitors. The designed derivatives were synthesised and evaluated in vitro as cytotoxic agents against two human cancer cell lines namely, HepG-2 and MCF-7. Also, the synthesised derivatives were assessed for their VEGFR-2inhibitory effect. The most promising member 11e were further investigated to reach a valuable insight about its apoptotic effect through cell cycle and apoptosis analyses. Moreover, deep investigations were carried out for compound 11e using western-plot analyses to detect its effect against some apoptotic and apoptotic parameters including caspase-9, caspase-3, BAX, and Bcl-2. Many in silico investigations including docking, ADMET, toxicity studies were performed to predict binding affinity, pharmacokinetic, drug likeness, and toxicity of the synthesised compounds. The results revealed that compounds 11e, 11g, 12e, 12g, and 12k exhibited promising cytotoxic activities (IC50 range is 2.1 - 9.8 µM), comparing to sorafenib (IC50 = 3.4 and 2.2 µM against MCF-7 and HepG2, respectively). Moreover, 11b, 11f, 11g, 12e, 12f, 12g, and 12k showed the highest VEGFR-2 inhibitory activities (IC50 range is 2.9 - 5.4 µM), comparing to sorafenib (IC50 = 3.07 nM). Additionally, compound 11e had good potential to arrest the HepG2 cell growth at G2/M phase and to induce apoptosis by 49.14% compared to the control cells (9.71%). As well, such compound showed a significant increase in the level of caspase-3 (2.34-fold), caspase-9 (2.34-fold), and BAX (3.14-fold), and a significant decrease in Bcl-2 level (3.13-fold). For in silico studies, the synthesised compounds showed binding mode similar to that of the reference compound (sorafenib).

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.

Design, synthesis, docking, and anticancer evaluations of phthalazines as VEGFR-2 inhibitors

Twenty new N-substituted-4-phenylphthalazin-1-amine derivatives were designed, synthesized, and evaluated for their anticancer activities against HepG2, HCT-116, and MCF-7 cells as VEGFR-2 inhibitors. HCT-116 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 7f was found to be the most potent derivative among all the tested compounds against the three cancer cell lines, with 50% inhibition concentration, IC₅₀  = 3.97, 4.83, and 4.58 µM, respectively, which is more potent than both sorafenib (IC₅₀  = 9.18, 5.47, and 7.26 µM, respectively) and doxorubicin (IC₅₀  = 7.94, 8.07, and 6.75 µM, respectively). Fifteen of the synthesized derivatives were selected to evaluate their inhibitory activities against VEGFR-2. Compound 7f was found to be the most potent derivative that inhibited VEGFR-2 at an IC₅₀ value of 0.08 µM, which is more potent than sorafenib (IC₅₀  = 0.10 µM). Compound 8c inhibited VEGFR-2 at an IC₅₀ value of 0.10 µM, which is equipotent to sorafenib. Moreover, compound 7a showed very good activity with IC₅₀ values of 0.11 µM, which is nearly equipotent to sorafenib. In addition, compounds 7d, 7c, and 7g possessed very good VEGFR-2-inhibitory activity, with IC₅₀ values of 0.14, 0.17, and 0.23 µM, respectively.

Identification of new [1,2,4]triazolo[4,3-a]quinoxalines as potent VEGFR-2 tyrosine kinase inhibitors: Design, synthesis, anticancer evaluation, and in silico studies

Tumor angiogenesis is mainly regulated by VEGFR-2. In this study, a new series of [1,2,4]triazolo[4,3-a]quinoxaline based-derivatives has been designed and synthesized to develop new anti-proliferative and anti-VEGFR-2 members. Anti-proliferative activities of the synthesized compounds were tested against MCF-7 and HepG2 cell lines. Compound 19a exhibited the highest activity towards both MCF-7 and HepG2 cell lines (IC₅₀ = 8.2 and 5.4 µM, respectively), compared to sorafenib (IC₅₀ = 3.51 and 2.17 µM, respectively). Additionally, all compounds were screened to evaluate their effect as VEGFR-2 inhibitors. Compound 19a (IC₅₀ = 3.4 nM) exhibited good activity compared to sorafenib (IC₅₀ = 3.12 nM). Furthermore, compound 19a disrupted the HepG2 cell cycle by arresting the G2/M phase. Also, marked increase in the percentage apoptotic cells was achieved by compound 19a. The induced apoptotic effect of compound 19a in HepG2 cells was assured by increased pro-apoptotic marker (Bax) expression by 2.33-fold and decreased anti-apoptotic (Bcl-2) expression by 1.88-fold, resulting in an elevation of the Bax/Bcl-2 ratio in HepG2 cells. Comparing to the control cells, compound 19a induced an increase in expression of cleaved caspase-3 and caspase-9 by 2.44- and 2.69-fold, respectively. Finally, the binding modes of the target derivatives were investigated through docking studies against the proposed molecular target (VEGFR-2, PDB ID: 2OH4).

Design, synthesis and molecular docking of new [1,2,4] triazolo[4,3-a]quinoxaline derivatives as anticancer agents targeting VEGFR-2 kinase

Vascular endothelial growth factor receptor-2 (VEGFR-2) is critically involved in cancer angiogenesis. Blocking of VEGFR-2 signaling pathway proved effective suppression of tumor growth. Accordingly, two series of new triazoloquinoxaline-based derivatives were designed and synthesized as VEGFR-2 inhibitors. All in vitro cytotoxic activities of the synthesized compounds were evaluated against two human cancer cell lines (MCF-7 and HepG2). To confirm the potential mechanism of cytotoxicity, enzymatic assays against VEGFR-2 were estimated for all the target compounds. The results of VEGFR-2 inhibitory activity and cytotoxicity were in high correlation. Compound 22a exhibited the highest cytotoxic effect with IC₅₀ values of 6.2 and 4.9 μM against MCF-7 and HepG2, respectively, comparing to sorafenib (IC₅₀ = 3.53 and 2.18 μM). Such derivative showed the best VEGFR-2 inhibitory activity with an IC₅₀ value of 3.9 nM, which is very close to that of sorafenib (IC₅₀ = 3.13 nM). Moreover, compounds 22b, 23b, and 23e exhibited strong cytotoxic activity with IC₅₀ values ranging from 11.7 to 15.3 μM. Also, these compounds showed promising VEGFR-2 inhibition with IC₅₀ values of 4.2, 5.7, and 4.7 nM, respectively. In silico docking, ADMET, and toxicity studies were carried out for the synthesized compounds. The results revealed that some compounds have a good binding mode against VEGFR-2 and a high level of drug-likeness.

Phthalazine-based VEGFR-2 inhibitors: Rationale, design, synthesis, in silico, ADMET profile, docking, and anticancer evaluations

In the designed compounds, a new linker was inserted in the form of fragments with verified VEGFR-2 inhibitory potential, including an α,β-unsaturated ketonic fragment, pyrazole, and pyrimidine. Also, new distal hydrophobic moieties were attached to these linkers that are expected to increase the hydrophobic interaction with VEGFR-2 and, consequently, the affinity. These structural optimizations have led us to identify the novel dihydropyrazole derivative 6_e as a promising hit molecule. All the new derivatives were evaluated to assess their anticancer activity against three human cancer cell lines, including HepG2, HCT-116, and MCF-7. The results of the in vitro anticancer evaluation study revealed the moderate to excellent cytotoxicity of 6_c , 6_e , 6_g , and 7_b , with IC₅₀ values in the low micromolar range. The inhibitory activity of VEGFR-2 was investigated for 16 of the designed compounds. The enzyme assay results of the new compounds were compared with those of sorafenib as a reference VEGFR-2 inhibitor. The obtained results demonstrated that our derivatives are potent VEGFR-2 inhibitors. The most potent derivatives 6_c , 6_e , 6_g , and 7_b showed IC₅₀ values in the range of 0.11-0.22 µM. Molecular docking and pharmacokinetic studies were also conducted to rationalize the VEGFR-2 inhibitory activity and to evaluate the ability of the most potent derivatives to be developed as good drug candidates.

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.

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.

Pyridine-derived VEGFR-2 inhibitors: Rational design, synthesis, anticancer evaluations, in silico ADMET profile, and molecular docking

Novel pyridine-derived compounds (5-19) were designed and synthesized, and their anticancer activities were evaluated against HepG2 and MCF-7 cells, targeting the VEGFR-2 enzyme. Compounds 10, 9, 8, and 15 were found to be the most potent derivatives against the two cancer cell lines, HepG2 and MCF-7, respectively, with IC₅₀  = 4.25 and 6.08 µM, 4.68 and 11.06 µM, 4.34 and 10.29 µM, and 6.37 and 12.83 µM. Compound 10 displayed higher activity against HepG2 cells than sorafenib (IC₅₀  = 9.18 and 5.47 µM, respectively) and doxorubicin (IC₅₀  = 7.94 and 8.07 µM, respectively). It also showed higher activity than doxorubicin against MCF-7 cells, but lower activity than sorafenib. Compounds 9, 8, and 15 displayed higher activities than sorafenib and doxorubicin against HepG2 cells but exhibited lower activities against MCF-7 cells. Compound 10 potently inhibited VEGFR-2 at an IC₅₀ value of 0.12 µM, which is nearly equipotent to sorafenib (IC₅₀  = 0.10 µM). Compounds 8 and 9 exhibited very good activity with the same IC₅₀ value of 0.13 µM. The six most potent derivatives, 6, 9, 8, 10, 15, and 18, were tested for their cytotoxicity against normal Vero cells. Compounds 6, 8, 9, 10, 15, and 18 are, respectively, 1.13, 3.74, 4.18, 3.64, 2.81, and 2.00 times more toxic to HepG2 and 2.06, 1.58, 1.76, 2.54, 1.40, and 2.69 times more toxic to MCF-7 breast cancer cells than in normal Vero cells.

New bis([1,2,4]triazolo)[4,3-a:3',4'-c]quinoxaline derivatives as VEGFR-2 inhibitors and apoptosis inducers: Design, synthesis, in silico studies, and anticancer evaluation

A new series of bis([1,2,4]triazolo)[4,3-a:3',4'-c]quinoxaline derivatives were designed and synthesized to have the main essential pharmacophoric features of VEGFR-2 inhibitors. VEGFR-2 inhibitory activities were assessed for the designed compounds. In addition, cytotoxic activity was evaluated for all derivatives against two human cancer cell lines namely, HepG-2 and MCF-7. The most cytotoxic compound 20 h was subjected to further biological investigations including cell cycle, apoptosis, caspase-3, caspase-9, BAX, and Bcl-2 analyses. Different in silico studies as docking, ADMET and toxicity were carried out. The results exhibited that compounds 20b, 20e, 20h and20mshowed promising VEGFR-2 inhibitory activities with IC₅₀values of 5.7, 6.7, 3.2, and 3.1 µM, respectively. Moreover, these promising members exhibited the highest antiproliferative activities against the two cell lines with IC₅₀values ranging from 3.3 to 14.2 µM, comparing to sorafenib (IC₅₀ = 2.17 and 3.43 µM against HepG2 and MCF-7, respectively). Additionally, compound 20h induced cell cycle arrest of HepG2 cells at G2/M phase. Also, such compound increased the progress of apoptosis by 3.5-fold compared to the control. As well, compound 20h showed a significant increase in the level of caspase-3 (2.07-fold), caspase-9 (1.72-fold), and BAX (1.83-fold), and a significant decrease in Bcl-2 level (1.92-fold). The in silico studies revealed that the synthesized compounds have binding pattern like that of sorafenib.

Design, microwave assisted synthesis, and molecular modeling study of some new 1,3,4-thiadiazole derivatives as potent anticancer agents and potential VEGFR-2 inhibitors

A green and efficient method was developed for the synthesis of 1,3,4-thiadiazole based compounds under microwave (MW) activation. The nucleophile N-(5-amino-1,3,4-thiadiazol-2-yl)thiophene-2-carboxamide (3) was synthesized and reacted with different carbon electrophilic reagents to afford thiadiazolo-pyrimidine or imidazolo-thiadiazoline derivatives (4-6 and 8), respectively. Furthermore, a one-pot reaction of 3 with p-chlorobenzaldehyde and different carbon electrophile/ or nucleophiles under microwave irradiation yields the cyclic thiadiazolo-pyrimidine derivatives 10-15. Additionally, nucleophilic substitution of aromatic amines and/or potassium salts of some heterocyclic compounds with chloroacetamido-thiadiazole 6 yields derivatives 16-20. All the new derivatives were synthesized by both conventional and MW irradiation methods. All the new 1,3,4-thiadiazole derivatives were evaluated against four cancer cell lines, HepG-2, MCF-7, HCT-116, and PC-3. The anti-proliferative activity of most of the synthesized compounds exhibited excellent broad-spectrum cytotoxic activity against the cancer cell lines with IC₅₀ values ranging from 3.97 to 9.62 μM. Moreover, the enzymatic assessment of five derivatives (2,4b, 6, 8, 9a) against VEGFR-2 tyrosine kinase showed significant inhibitory activities with IC₅₀ of 11.5, 8.2, 10.3, 10.5 and 9.4 nM respectively. Further studies revealed the ability of compound 9a to have a strong DNA-binding affinity of 36.06 μM via DNA/methyl green assay. Moreover, molecular docking study was carried out to reveal the binding interactions of compounds in the binding site of VEGFR-2 enzyme explaining the significant inhibitory activity of these derivatives. Finally, ADME/Tox studies was performed to predict the pharmacokinetics of the synthesized compounds.

Design, synthesis, docking, ADMET profile, and anticancer evaluations of novel thiazolidine-2,4-dione derivatives as VEGFR-2 inhibitors

The anticancer activity of novel thiazolidine-2,4-diones was evaluated against HepG2, HCT-116, and MCF-7 cells. Among the tested cancer cell lines, HCT-116 was the most sensitive one to the cytotoxic effect of the new derivatives. In particular, compounds 18, 11, and 10 were found to be the most potent derivatives among all the tested compounds against the HepG2, HCT-116, and MCF-7 cancer cell lines, with IC₅₀ values ranging from 38.76 to 53.99 µM. The most active antiproliferative derivatives (7-14 and 15-19) were subjected to further biological studies to evaluate their inhibitory potentials against VEGFR-2. The tested compounds displayed a good-to-medium inhibitory activity, with IC₅₀ values ranging from 0.26 to 0.72 µM. Among them, compounds 18, 11, and 10 potently inhibited VEGFR-2 at IC₅₀ values in the range of 0.26-0.29 µM, which are nearly three times that of the sorafenib IC₅₀ value (0.10 µM). Although our derivatives showed lower activities than the reference drug, they could be useful as a template for future design, optimization, adaptation, and investigation to produce more potent and selective VEGFR-2 inhibitors with higher anticancer analogs. The ADMET profile showed that compounds 18, 11, and 10 do not violate any of Lipinski's rules and have a comparable intestinal absorptivity in humans. Also, the new derivatives could not inhibit cytochrome P3A4. Unlike sorafenib and doxorubicin, compounds 18, 11, and 10 are expected to have prolonged dosing intervals. Moreover, compounds 10 and 18 displayed a wide therapeutic index and higher selectivity against cancer cells as compared with their cytotoxicity against normal cells.

New quinoxaline derivatives as VEGFR-2 inhibitors with anticancer and apoptotic activity: Design, molecular modeling, and synthesis

New series of [1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-one and [1,2,4]triazolo[4,3-a]quinoxaline derivatives have been designed, synthesized, and biologically assessed for their anti-proliferative activities against two selected tumor cell lines MCF-7 and HepG2. Comparing to sorafenib (IC₅₀ = 2.17 ± 0.13 and 3.51 ± 0.21 µM against MCF-7 and HepG2, respectively), compound 25d, 25e, 25i, and 27e exhibited the highest activities against the examined cell lines with IC₅₀ values extending from 4.1 ± 0.4 to 11.7 ± 1.1 µM. Furthermore, VEGFR-2 inhibitory activities were assessed for all the synthesized compounds as potential mechanisms for their anti-proliferative activities. Compounds 25d, 25e, 25i, and 27e displayed prominent inhibitory efficiency versus VEGFR-2 kinase with IC₅₀ value ranging from 3.4 ± 0.3 to 6.8 ± 0.5 nM. Fascinatingly, the results of VEGFR-2 inhibitory assays were matched with that of the cytotoxicity data, where the most potent anti-proliferative derivatives exhibited promising VEGFR-2 inhibitory activities. Further studies displayed the ability of compound 25d to induce apoptosis in HepG2 cells and can arrest the growth of such cells at the G2/M phase. Also, compound 25d produced a significant increase in the level of BAX/Bcl-2 ratio (3.8-fold), caspase- 3 (1.8-fold), and caspase-9 (1.9-fold) compared to the control cells. Molecular docking studies were carried out to investigate the possible binding interaction inside the active site of the VEGFR-2.

Design, synthesis, molecular docking, in silico ADMET profile and anticancer evaluations of sulfonamide endowed with hydrazone-coupled derivatives as VEGFR-2 inhibitors

A new series of sulfonamide endowed with hydrazone coupled to dimethyl and/or diethyl malonates were prepared. Various sulfa drugs were diazotized and followed by coupling with active methylene of dimethyl and/or diethyl malonate to afford the new intermediates hydrazones 3_a-c and 4_a-c. The reactivity of hydrazone derivatives towards hydrazines was investigated. Thus, a novel series of 3,5-dioxopyrazolidine7_a-cwere obtained by treatment with hydrazine hydrate. When hydrazones were allowed to react with phenyl hydrazine, the alkyl 2-((4-(N-(substituted)sulfamoyl)phenyl)diazenyl)-3-oxo-3-(2-phenylhydrazinyl)propanoateswere obtained 8_a-c and/or 10_a-c. Their anticancer activities were evaluated against HepG2, HCT-116 and MCF-7. HepG2 was the most sensitive one. In particular, compounds 7_c, 7_b and 10_c were found to be the most potent derivatives with IC₅₀ = 6.43 ± 0.5, 9.66 ± 0.8, 10.57 ± 0.9 µM, 8.65 ± 0.7, 7.49 ± 0.6, 14.29 ± 1.3 µM and 8.97 ± 0.7, 10.13 ± 0.9, 13.82 ± 1.1 µM respectively. Sorafenib and doxorubicin were used as reference drugs. The most potent derivatives 7_a, 7_b, 7_c, 8_c and 10_c were tested for their cytotoxicity against normal VERO cell lines. Compounds 7_a, 7_b, 7_c, 8_c and 10_c are respectively, 2.41, 4.85, 4.08, 3.23 and 5.89 fold times more toxic in HCT116 than in VERO normal cells. Moreover, the most active anti-proliferative derivatives 7_a, 7_b, 7_c, 8_c and 10_c were subjected to further biological study to evaluate their inhibitory potentials against VEGFR-2. The tested compounds displayed high to good inhibitory activity with IC₅₀ values ranging from 0.14 ± 0.02 to 0.23 ± 0.03 µM. Among them, compounds 7_c, 7_b and 10_c were found to be the most potent derivative that inhibited VEGFR-2 at IC₅₀ values of 0.14 ± 0.02, 0.15 ± 0.02 and 0.15 ± 0.02 µM respectively. sorafenib was used as reference drug. Furthermore, ADMET profile was evaluated for the four most active compounds in comparison to doxorubicin as a reference drug. The data obtained from docking studies were highly correlated with that obtained from the biological screening.

Design, molecular docking, in vitro, and in vivo studies of new quinazolin-4(3H)-ones as VEGFR-2 inhibitors with potential activity against hepatocellular carcinoma

A series of new VEGFR-2 inhibitors were designed, synthesized and evaluated for their anti-proliferative activities against hepatocellular carcinoma (HepG-2 cell line). Compound 29_b (IC₅₀ = 4.33 ± 0.2 µg/ml) was found to be the most potent derivative as it has showed to be more active than doxorubicin (IC₅₀ = 4.50 ± 0.2 µg/ml) and 78% of sorafenib activity (IC₅₀ = 3.40 ± 0.25 µg/ml). The inhibitory profiles against VEGFR-2 were also assessed for the most promising candidates (16_b, 20_c, 22_b, 24_a, 24_b, 28_c, 28_e, 29_a, 29_b and 29_c). Compounds 29_b, 29_c and 29_a exhibited potent inhibitory activities towards VEGFR-2 at IC₅₀ values of 3.1 ± 0.04, 3.4 ± 0.05 and 3.7 ± 0.06 µM, respectively, comparing sorafenib (IC₅₀ = 2.4 ± 0.05 µM). Furthermorer, compound 29_b induced apoptosis and arrested the cell cycle growth at G2/M phase. Additionally, in vivo antitumor experiments revealed that compounds 29_b and 29_c have significant tumor growth inhibition. The test of immuno-histochemical expression of activated caspase-3 revealed that there is a time-dependent increase in cleaved caspase-3 protein expression upon exposure of HepG-2 cells to compound 29_b. Moreover, the fibroblastic proliferative index test revealed that compound 29_b could attenuate liver fibrosis. Docking studies also supported the results concluded from the biological screening via prediction of the possible binding interactions of the target compounds with VEGFR-2 active sites using the crystal structure of VEGFR-2 downloaded from the Protein Data Bank, (PDB ID: 2OH4) using Discovery Studio 2.5 software. Further structural optimization of the most active candidates may serve as a useful strategy for getting new lead compounds in search for powerful and selective antineoplastic agents.

N-Substituted-4-phenylphthalazin-1-amine-derived VEGFR-2 inhibitors: Design, synthesis, molecular docking, and anticancer evaluation studies

In accordance with the significant impetus of the discovery of potent vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitors, herein, we report the design, synthesis, and anticancer evaluation of 12 new N-substituted-4-phenylphthalazin-1-amine derivatives against HepG2, HCT-116, and MCF-7 cells as VEGFR-2 inhibitors. The results of the cytotoxicity investigation indicated that HCT-116 and MCF-7 were the most sensitive cell lines to the influence of the newly synthesized derivatives. In particular, compound 7a was found to be the most potent derivative among all the tested compounds against the three cancer cell lines, HepG2, HCT116, and MCF-7, with IC₅₀  = 13.67 ± 1.2, 5.48 ± 0.4, and 7.34 ± 0.6 µM, respectively, which is nearly equipotent to that of sorafenib (IC₅₀  = 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively). All synthesized derivatives, 4a,b-8a-c, were evaluated for their inhibitory activities against VEGFR-2. The tested compounds displayed high to low inhibitory activity, with IC₅₀ values ranging from 0.14 ± 0.02 to 9.54 ± 0.85 µM. Among them, compound 7a was found to be the most potent derivative that inhibited VEGFR-2 at an IC₅₀ value of 0.14 ± 0.02 µM, which is nearly 72% of that of the sorafenib IC₅₀ value (0.10 ± 0.02 µM). Compounds 7b, 8c, 8b, and 8a exhibited very good activity with IC₅₀ values of 0.18 ± 0.02, 0.21 ± 0.03, 0.24 ± 0.02, and 0.35 ± 0.04 µM, respectively. Molecular modeling studies were carried out for all compounds against the VEGFR-2 active site. The data obtained from biological testing highly correlated with that obtained from molecular modeling studies. However, these modifications led to new phthalazine derivatives with higher VEGFR-2 inhibitory activities than vatalanib and which are nearly equipotent to sorafenib.

Design, synthesis, molecular docking, anticancer evaluations, and in silico pharmacokinetic studies of novel 5-[(4-chloro/2,4-dichloro)benzylidene]thiazolidine-2,4-dione derivatives as VEGFR-2 inhibitors

The anticancer activity of novel thiazolidine-2,4-diones was evaluated against HepG2, HCT-116, and MCF-7 cells. MCF-7 was the most sensitive cell line to the cytotoxicity of the new derivatives. In particular, compounds 18, 12, 17, and 16 were found to be the most potent derivatives over all the tested compounds against the cancer cell lines HepG2, HCT116, and MCF-7, with IC₅₀  = 9.16 ± 0.9, 8.98 ± 0.7, 5.49 ± 0.5 µM; 9.19 ± 0.5, 8.40 ± 0.7, 6.10 ± 0.4 µM; 10.78 ± 1.2, 8.87 ± 1.5, 7.08 ± 1.6 µM; and 10.87 ± 0.8, 9.05 ± 0.7, 7.32 ± 0.4 µM, respectively. Compounds 18 and 12 have nearly the same activities as sorafenib (IC₅₀  = 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively), against HepG2 cells, but slightly lower activity against HCT116 cells and slightly higher activity against the MCF-7 cancer cell line. Also, these compounds displayed lower activities than doxorubicin against HepG2 and HCT-116 cells but higher activity against MCF-7 cells (IC₅₀  = 7.94 ± 0.6, 8.07 ± 0.8, and 6.75 ± 0.4 µM, respectively). In contrast, compounds 17 and 16 exhibited lower activities than sorafenib against HepG2 and HCT116 cells, but nearly equipotent activity against the MCF-7 cancer cell line. Also, these compounds displayed lower activities than doxorubicin against the three cell lines. All the synthesized derivatives 7-18 were evaluated for their inhibitory activities against VEGFR-2. The tested compounds displayed high to medium inhibitory activity, with IC₅₀ values ranging from 0.17 ± 0.02 to 0.27 ± 0.03 µM. Compounds 18, 12, 17, and 16 potently inhibited VEGFR-2 at IC₅₀ values of 0.17 ± 0.02, 0.17 ± 0.02, 0.18 ± 0.02, and 0.18 ± 0.02 µM, respectively, which are nearly more than half of that of the IC₅₀ value for sorafenib (0.10 ± 0.02 µM).

Design, synthesis, molecular docking and anticancer evaluations of 5-benzylidenethiazolidine-2,4-dione derivatives targeting VEGFR-2 enzyme

Novel series of 5-benzylidenethiazolidine-2,4-dione derivatives 4_a-c-8_a-f were designed, synthesized and evaluated for anticancer activity against HepG2, HCT-116 and MCF-7 cell lines. MCF-7 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 8_f was found to be the most potent derivative overall the tested compounds against the three HepG2, HCT116 and MCF-7 cancer cell lines with IC₅₀ = 11.19 ± 0.8, 8.99 ± 0.7 and 7.10 ± 0.4 µM respectively. Compound 8_f exhibited lower activity than sorafenib, (IC₅₀ = 9.18 ± 0.6, 8.37 ± 0.7 and 5.10 ± 0.4 µM respectively), against HepG2 and HCT116 but exhibited nearly the same activity against MCF-7 cancer cell lines respectively. Also, this compound displayed lower activity than doxorubicin, (IC₅₀ = 7.94 ± 0.6, 8.07 ± 0.8 and 6.75 ± 0.4 µM respectively), against HepG2 and HCT116 but nearly the same activity against MCF-7cell lines respectively. The most active derivatives 6_c,d,f,g and 8_a-f were evaluated for their inhibitory activities against VEGFR-2. The elongation of the structures to have distal moieties enhanced anticancer and VEGFR-2 inhibitory activities as in compounds 8_a-f. Among them, compounds 8_f was found to be the most potent derivative that inhibited VEGFR-2 at IC₅₀ value of 0.22 ± 0.02 µM, which is nearly the half as that of sorafenib IC₅₀ value (0.10 ± 0.02 µM). Furthermore, molecular design was performed to investigate their binding mode and affinities towards VEGFR-2 receptor. The data obtained from docking studies were highly correlated with that obtained from the biological screening.

5-(4-Methoxybenzylidene)thiazolidine-2,4-dione-derived VEGFR-2 inhibitors: Design, synthesis, molecular docking, and anticancer evaluations

A novel series of 5-(4-methoxybenzylidene)thiazolidine-2,4-dione derivatives, 5a-g and 7a-f, was designed, synthesized, and evaluated for their anticancer activity against HepG2, HCT116, and MCF-7 cells. HepG2 and HCT116 were the most sensitive cell lines to the influence of the new derivatives. In particular, compounds 7f, 7e, 7d, and 7c were found to be the most potent derivatives of all the tested compounds against the HepG2, HCT116, and MCF-7 cancer cell lines. Compound 7f (IC₅₀  = 6.19 ± 0.5, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively) exhibited a higher activity than sorafenib (IC₅₀  = 9.18 ± 0.6, 8.37 ± 0.7, and 5.10 ± 0.4 µM, respectively) against HepG2 and MCF-7, cells but a lower activity against HCT116 cancer cells, respectively. Also, this compound displayed a higher activity than doxorubicin (IC₅₀  = 7.94 ± 0.6, 8.07 ± 0.8, and 6.75 ± 0.4 µM, respectively) against HepG2 and MCF-7 cells, but nearly the same activity against HCT116 cells, respectively. All derivatives, 5a-g and 7a-f, were evaluated for their inhibitory activities against vascular endothelial growth factor receptor-2 (VEGFR-2). Among them, compound 7f was found to be the most potent derivative that inhibited VEGFR-2 at an IC₅₀ value of 0.12 ± 0.02 µM, which is nearly the same as that of sorafenib (IC₅₀  = 0.10 ± 0.02 µM). Compounds 7e, 7d, 7c, and 7b exhibited the highest activity, with IC₅₀ values of 0.13 ± 0.02, 0.14 ± 0.02, 0.14 ± 0.02, and 0.18 ± 0.03 µM, respectively, which are more than the half of that of sorafenib. Furthermore, molecular docking was performed to investigate their binding mode and affinities toward the VEGFR-2 receptor. The data obtained from the docking studies highly correlated with those obtained from the biological screening.

Towards discovery of novel scaffold with potent antiangiogenic activity; design, synthesis of pyridazine based compounds, impact of hinge interaction, and accessibility of their bioactive conformation on VEGFR-2 activities

Pyridazine scaffolds are considered privileged structures pertaining to its novelty, chemical stability, and synthetic feasibility. In our quest towards the development of novel scaffolds for effective vascular endothelial growth 2 (VEGFR-2) inhibition with antiangiogenic activity, four novel series of pyridazines were designed and synthesised. Five of the synthesised compounds; namely (8c, 8f, 15, 18b, and 18c) exhibited potent VEGFR-2 inhibitory potency (>80%); with IC₅₀ values ranging from low micromolar to nanomolar range; namely compounds 8c, 8f, 15, 18c with (1.8 µM, 1.3 µM, 1.4 µM, 107 nM), respectively. Moreover, 3-[4-{(6-oxo-1,6-dihydropyridazin-3-yl)oxy}phenyl]urea derivative (18b) exhibited nanomolar potency towards VEGFR-2 (60.7 nM). In cellular assay, the above compounds showed excellent inhibition of VEGF-stimulated proliferation of human umbilical vein endothelial cells at 10 μM concentration. Finally, an extensive molecular simulation study was performed to investigate the probable interaction with VEGFR-2.

Ramucirumab for the treatment of gastric or gastro-esophageal junction cancer

Introduction: Gastric cancer remains one of the most lethal malignancy, accounting for an estimated 783,000 deaths worldwide in 2018. Although there are several approved drugs for the treatment of gastric cancer, the survival of patients with advanced disease remains dismal. Ramucirumab, a vascular endothelial growth factor receptor-2 inhibitor, is an important new targeted drug approved for gastric and gastroesophageal adenocarcinoma (GEJ) in second-line setting. Areas covered: In this article, we have reviewed the role of ramucirumab in the management of gastric and GEJ adenocarcinoma. A comprehensive review of various clinical trials is presented that support the use of ramucirumab in gastric cancer. Expert opinion: In our opinion, ramucirumab should be considered as a standard of care option, either alone or with paclitaxel, after progression on first-line therapy for advanced or metastatic disease. The results of large, randomized phase III clinical trials show benefit of ramucirumab on median overall survival (OS). However, the benefit is limited, with only about two months OS benefit of using ramucirumab with paclitaxel compared to paclitaxel alone. Novel combination therapies, such as ramucirumab with other targeted agents and immune checkpoint inhibitors in ongoing clinical trials, may provide important information to further improve the patient outcomes.

Design and synthesis of novel pyridazinoquinazoline derivatives as potent VEGFR-2 inhibitors: In vitro and in vivo study

Worldwide, Hepatocellular Carcinoma (HCC) endures to be a prominent cause of cancer death. Treatment of HCC follows multiple therapies which are not entirely applicable for treatment of all patients. HCC usually arises contextual to chronic liver diseases and is often discovered at later stages which makes treatment options more complex. The present study aimed at design, synthesis & evaluation of new pyridazinoquinazoline derivatives as potential nontoxic anti-hepatocellular carcinoma (HCC) agents, through inhibition of Vascular endothelial growth factor -2 (VEGFR-2). Novel Pyridazino[3, 4, 5-de]quinazoline derivatives (2-6) were designed & synthesized. Their structures were confirmed via spectral and microanalytical data. They were tested for their in vitro VEGFR-2 inhibition & anticancer activity against human liver cancer cell line (HEPG-2). Molecular docking was investigated into VEGFR-2 site. In vivo studies of VEGRF-2 inhibition and the anti-apoptotic effect of the new compounds were determined in liver of irradiated rats. Toxicity of synthesized compounds was also assessed. The results showed that compounds 3-6 have significant antitumor activity and proved to be non-toxic. The ethoxy aniline derivative 6, exhibited the highest activity both in vitro and in vivo compared to the reference drug used, sorafenib. Compound 6 could be considered a promising nontoxic anti HCC agent and this could be partially attributed to its VEGFR-2 inhibition. Future preclinical investigation would be carried out to confirm the specific and exact mechanism of action of these derivatives especially compound 6 as an effective pharmaceutical agent after full toxicological and pharmacological assessment.

Protein-ligand interaction-guided discovery of novel VEGFR-2 inhibitors

As an effective target in abnormal angiogenesis-related tumor treatment, VEGFR-2 has small-molecule inhibitors of various scaffolds being approved for treating diseases such as renal carcinoma, non-small cell lung cancer, etc. However, endogenous and acquired drug resistance are still considered to be the main contributors for the failure of VEGFR-2 clinical candidates. Therefore, development of novel VEGFR-2 inhibitors is still urgently needed in the market but also challenging. In this work, residues including Asp1046, Ile1025, HIS1026, Cys919 and Lys868 were identified as the most important residues for Hbonded interaction, while His1026, Asp1046, Glu885, Ile1025 and Leu840 exhibited critical role for the nonbonded interactions through a comprehensive analysis of protein-ligand interactions, which plays critical roles in the binding of compounds and targets. Guided by the analysis of binding interactions, a total of 10 novel VEGFR-2 inhibitors based on N-methyl-4-oxo-N-propyl-1,4-dihydroquinoline-2-carboxamide scaffold were discovered through fragment-based drug design and structure-based virtual screening, which expands the chemical space of current VEGFR-2 inhibitors. Biological activity evaluation showed that even though the enzymatic activity of these compounds against VEGFR-2 were inferior to that of the positive controls sorafenib and motesanib, compound I-10 showed moderate HepG2 cell inhibitory activity with an IC₅₀ value of 33.65 μM and eight compounds exhibited moderate or higher HUVEC inhibitory activity in the range of 19.54-57.98 μM compared to the controls. Particularly, the HUVEC inhibitory activity of compound I-6 (IC₅₀ = 19.54 μM) outperformed motesanib and can be used as starting points for further optimization and development for cancer treatment.Communicated by Ramaswamy H. Sarma.

Enhancement of the tail hydrophobic interactions within the carbonic anhydrase IX active site via structural extension: Design and synthesis of novel N-substituted isatins-SLC-0111 hybrids as carbonic anhydrase inhibitors and antitumor agents

Herein we report the design and synthesis of novel N-substituted isatins-SLC-0111 hybrids (6a-f and 9a-l). A structural extension approach was adopted via N-alkylation and N-benzylation of isatin moiety to enhance the tail hydrophobic interactions within the carbonic anhydrase (CA) IX active site. Thereafter, a hybrid pharmacophore approach was utilized via merging the pharmacophoric elements of isatin and SLC-0111 in a single chemical framework. As planned, a substantial improvement of inhibitory profile of the target hybrids (K_Is: 4.7-86.1 nM) towards hCA IX in comparison to N-unsubstituted leads IVa-c (K_Is: 192-239 nM), was achieved. Molecular docking of the designed hybrids in CA IX active site unveiled, as planned, the ability of N-alkylated and N-benzylated isatin moieties to accommodate in a wide hydrophobic pocket formed by T73, P75, P76, L91, L123 and A128, establishing strong van der Waals interactions. Hybrid 6c displayed good anti-proliferative activity under hypoxic conditions towards breast cancer MDA-MB-231 and MCF-7 cell lines (IC₅₀ = 7.43 ± 0.28 and 12.90 ± 0.34 μM, respectively). Also, 6c disrupted the MDA-MB-231 cell cycle via alteration of the Sub-G₁ phase and arrest of G₂-M stage. Additionally, 6c displayed significant increase in the percent of annexinV-FITC positive apoptotic cells from 1.03 to 18.54%. Furthermore, 6c displayed potent VEGFR-2 inhibitory activity (IC₅₀ = 260.64 nM). Collectively, these data suggest 6c as a promising lead molecule for the development of effective anticancer agents.

Molecular Design and Synthesis of New 3,4-Dihydropyrimidin-2(1H)-Ones as Potential Anticancer Agents with VEGFR-2 Inhibiting Activity

BACKGROUND

Two series of 3,4-dihydropyrimidin-2(1H)-one derivatives were designed based on the main structural features characterizing reported anticancer compounds with potent VEGFR-2 inhibiting activity.

METHODS

All the target compounds were synthesized and investigated for their in vitro anticancer activity using MTT assay and NCI protocol. The most active compounds were further investigated for the VEGFR-2 inhibiting activity using enzyme inhibition assay.

RESULT

Of these derivatives, compound 8b possessed significant activity against Caco-2 (IC50 of 24.9 µM) and MCF7 (IC50 of 29.4 µM), compound 10 showed excellent potency against HCT-116 (IC50 of 32.6 µM), HEPG2 (IC50 of 16.4 µM) and MCF7 (IC50 of 32.8 µM), while compound 11b exhibited moderate anticancer activity towards MCF7 (IC50 of 41.7µM). Both 8b and 10 exhibited good potency regarding the inhibition of vascular endothelial growth factor receptor 2 (VEGFR-2), with an IC50 of 14.00 and 21.62 nM, respectively.

CONCLUSION

The activity was rationalized based on molecular docking study that supported their VEGFR-2 inhibitory activity; as indicated by their favorable binding with the active site.

1-Piperazinylphthalazines as potential VEGFR-2 inhibitors and anticancer agents: Synthesis and in vitro biological evaluation

In our endeavor towards the development of effective VEGFR-2 inhibitors, three novel series of phthalazine derivatives based on 1-piperazinyl-4-arylphthalazine scaffold were synthesized. All the newly prepared phthalazines 16a-k, 18a-e and 21a-g were evaluated in vitro for their inhibitory activity against VEGFR-2. In particular, compounds 16k and 21d potently inhibited VEGFR-2 at sub-micromolar IC50 values 0.35 ± 0.03 and 0.40 ± 0.04 μM, respectively. Moreover, seventeen selected compounds 16c-e, 16g, 16h, 16j, 16k, 18c-e and 21a-g were evaluated for their in vitro anticancer activity according to US-NCI protocol, where compounds 16k and 21d proved to be the most potent anticancer agents. While, compound 16k exhibited potent broad spectrum anticancer activity with full panel GI50 (MG-MID) value of 3.62 μM, compound 21d showed high selectivity toward leukemia and prostate cancer subpanels [subpanel GI50 (MG-MID) 3.51 and 5.15 μM, respectively]. Molecular docking of compounds16k and 21d into VEGFR-2 active site was performed to explore their potential binding mode.

Part 5: Exploration of diverse hinge-binding fragments via core-refining approach

Pathological angiogenesis plays a critical role in numerous diseases including malignancy. VEGFR-2 is the central regulators in angiogenesis and has become a promising target for anticancer drug design. We have identified a novel biphenyl-aryl urea incorporated with salicyladoxime (BPS-7) as potent VEGFR-2 inhibitor. As a continuation to our previous research, various aromatic-heterocyclic were introduced as hinge-binding fragment via a core-refining approach. Interestingly, many compounds exhibited comparable VEGFR-2 inhibition to Sorafenib. In particular, 12e and 12o displayed excellent VEGFR-2 inhibitory activity with IC₅₀ values of 0.50 nM and 0.79 nM, respectively. Several title compounds showed considerable antiproliferative activity against A549 and SMMC-7721 cells. In addition, molecular docking was performed to rationalize the efficiency of the better compounds. These results will be instructive for further inhibitor design and optimization.