Discovery of new pyrimidine-5-carbonitrile derivatives as anticancer agents targeting EGFRWT and EGFRT790M

Design, synthesis, docking, ADMET studies, and anticancer evaluation of new 3-methylquinoxaline derivatives as VEGFR-2 inhibitors and apoptosis inducers

Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a critical role in cancer angiogenesis. Inhibition of VEGFR-2 activity proved effective suppression of tumour propagation. Accordingly, two series of new 3-methylquinoxaline derivatives have been designed and synthesised as VEGFR-2 inhibitors. The synthesised derivatives were evaluated in vitro for their cytotoxic activities against MCF-7and HepG2 cell lines. In addition, the VEGFR-2 inhibitory activities of the target compounds were estimated to indicate the potential mechanism of their cytotoxicity. To a great extent, the results of VEGFR-2 inhibition were highly correlated with that of cytotoxicity. Compound 27a was the most potent VEGFR-2 inhibitor with IC50 of 3.2 nM very close to positive control sorafenib (IC50 = 3.12 nM). Such compound exhibited a strong cytotoxic effect against MCF-7 and HepG2, respectively with IC50 of 7.7 and 4.5 µM in comparison to sorafenib (IC50 = 3.51 and 2.17 µM). In addition, compounds 28, 30f, 30i, and 31b exhibited excellent VEGFR-2 inhibition activities (IC50 range from 4.2 to 6.1 nM) with promising cytotoxic activity. Cell cycle progression and apoptosis induction were investigated for the most active member 27a. Also, the effect of 27a on the level of caspase-3, caspase-9, and BAX/Bcl-2 ratio was determined. Molecular docking studies were implemented to interpret the binding mode of the target compounds with the VEGFR-2 pocket. Furthermore, toxicity and ADMET calculations were performed for the synthesised compounds to study their pharmacokinetic profiles.

Inhibition of Vascular Smooth Muscle and Cancer Cell Proliferation by New VEGFR Inhibitors and Their Immunomodulator Effect: Design, Synthesis, and Biological Evaluation

Abnormal vascular smooth muscle cell (VSMC) proliferation has an important role in the pathogenesis of both atherosclerosis restenosis and hypertension. Vascular endothelial growth factor (VEGF) has been shown to stimulate VSMC proliferation. In addition, angiogenesis is one of the hallmarks of cancerous growth. VEGF is the key modulator for the initial stages of angiogenesis that acts through the endothelial-specific receptor tyrosine kinases (VEGFRs). VEGFR-2 blockage is a good approach for suppression of angiogenesis. In order to discover novel VEGFR-2 TK inhibitors, we have designed and synthesized three new series of pyridine-containing compounds. The new compounds were all screened against a panel of three cell lines (HepG-2, HCT-116, and MCF-7). Promising results encouraged us to additionally evaluate the most active members for their in vitro VEGFR-2 inhibitory effect. Compound 7a, which is the most potent candidate, revealed a significant increase in caspase-3 level by 7.80-fold when compared to the control. In addition, Bax and Bcl-2 concentration levels showed an increase in the proapoptotic protein Bax (261.4 Pg/ml) and a decrease of the antiapoptotic protein Bcl-2 (1.25 Pg/ml) compared to the untreated cells. Furthermore, compound 7a arrested the cell cycle in the G2/M phase with induction of apoptosis. The immunomodulatory effect of compound 7a, the most active member, showed a reduction in TNF-α by 87%. Also, compound 7a caused a potent inhibitory effect on smooth muscle proliferation. Docking studies were also performed to get better insights into the possible binding mode of the target compounds with VEGFR-2 active sites.

In Silico Exploration of Potential Natural Inhibitors against SARS-Cov-2 nsp10

In continuation of our previous effort, different in silico selection methods were applied to 310 naturally isolated metabolites that exhibited antiviral potentialities before. The applied selection methods aimed to pick the most relevant inhibitor of SARS-CoV-2 nsp10. At first, a structural similarity study against the co-crystallized ligand, S-Adenosyl Methionine (SAM), of SARS-CoV-2 nonstructural protein (nsp10) (PDB ID: 6W4H) was carried out. The similarity analysis culled 30 candidates. Secondly, a fingerprint study against SAM preferred compounds 44, 48, 85, 102, 105, 182, 220, 221, 282, 284, 285, 301, and 302. The docking studies picked 48, 182, 220, 221, and 284. While the ADMET analysis expected the likeness of the five candidates to be drugs, the toxicity study preferred compounds 48 and 182. Finally, a density-functional theory (DFT) study suggested vidarabine (182) to be the most relevant SARS-Cov-2 nsp10 inhibitor.

Epidermal growth factor receptor inhibitors as potential anticancer agents: An update of recent progress

Epidermal growth factor receptor (EGFR) is a vital intermediate in cell signaling pathway including cell proliferation, angiogenesis, apoptosis, and metastatic spread and also having four divergent members with similar structural features, such as EGFR (HER1/ErbB1), ErbB2 (HER2/neu), ErbB3 (HER3), and ErbB4 (HER4). Despite this, clinically exploited inhibitors of EGFR (including erlotinib, lapatinib, gefitinib, selumetinib, etc.) are not specific thus provoking unenviable adverse effects. Some of the paramount obstacles to generate and develop new lead molecules of EGFR inhibitors are drug resistance, mutation, and also selectivity which inspire medicinal chemists to generate novel chemotypes. The discovery of therapeutic agents that inhibit the precise stage in tumorous cells such as EGFR is one of the chief successful targets in many cancer therapies, including lung and breast cancers. This review aims to compile the various recent progressions (2016-2021) in the discovery and development of diverse epidermal growth factor receptor (EGFR) inhibitors belonging to distinct structural classes like pyrazoline, pyrazole, imidazole, pyrimidine, coumarin, benzothiazole, etc. We have summarized preclinical and clinical data, structure-activity relationships (SAR) containing mechanistic and in silico studies to provide proposals for the design and invention of new EGFR inhibitors with therapeutic significance. The detailed progress of the work in the field will provide inexorable scope for the development of novel drug candidates with greater selectivity and efficacy.

Quinazolin-4(3H)-one based potential multiple tyrosine kinase inhibitors with excellent cytotoxicity

A series of quinazolin-4(3H)-one derivatives were synthesised and evaluated for their cytotoxicity against human Caucasian breast adenocarcinoma (MCF-7) and human ovarian carcinoma (A2780) cell lines. Cytotoxicity of the most tested compounds was 2- to 30-fold more than the positive control lapatinib (IC₅₀ of 2j = 3.79 ± 0.96; 3j = 0.20 ± 0.02; and lapatinib = 5.9 ± 0.74) against MCF7 cell lines except two compounds (IC₅₀ of 2 b = 15.72 ± 0.07 and 2e = 14.88 ± 0.99). On the other hand, cytotoxicity was 4 − 87 folds (IC₅₀ of 3a = 3.00 ± 1.20; 3 g = 0.14 ± 0.03) more the positive control lapatinib (IC₅₀ = 12.11 ± 1.03) against A2780 cell lines except compound 2e (IC₅₀ = 16.43 ± 1.80). Among the synthesised quinazolin-4(3H)-one derivatives, potent cytotoxic 2f-j and 3f-j were investigated for molecular mechanism of action. Inhibitory activities of the compounds were tested against multiple tyrosine protein kinases (CDK2, HER2, EGFR and VEGFR2) enzymes. As expected, all the quinazolin-4(3H)-one derivatives were showed comparable inhibitory activity against those kinases tested, especially, compound 2i and 3i showed potent inhibitory activity against CDK2, HER2, EGFR tyrosine kinases. Therefore, molecular docking analysis for quinazolin-4(3H)-one derivatives 2i and 3i were performed, and it was revealed that compounds 2i and 3i act as ATP non-competitive type-II inhibitor against CDK2 kinase enzymes and ATP competitive type-I inhibitor against EGFR kinase enzymes. However, in case of HER2, compounds 2i act as ATP non-competitive type-II inhibitor and 3i act as ATP competitive type-I inhibitor. Docking results of known inhibitors were compared with synthesised compounds and found synthesised 2i and 3i are superior than the known inhibitors in case of interactions. In addition, in silico drug likeness properties of quinazolin-4(3H)-one derivatives showed better predicted ADME values than lapatinib.

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).

New quinoxaline-based VEGFR-2 inhibitors: design, synthesis, and antiproliferative evaluation with in silico docking, ADMET, toxicity, and DFT studies

A new series of 3-methylquinoxaline-based derivatives having the same essential pharmacophoric features as VEGFR-2 inhibitors have been synthesized and evaluated for their antiproliferative activities against two human cancer cell lines, MCF-7 and HepG-2. Compounds 15b and 17b demonstrated a significant antiproliferative effect with IC₅₀ ranging from 2.3 to 5.8 μM. An enzymatic assay was carried out for all the tested candidates against VEGFR-2. Compound 17b was the most potent VEGFR-2 inhibitor (IC₅₀ = 2.7 nM). Mechanistic investigation including cell cycle arrest and apoptosis was performed for compound 17b against HepG-2 cells, and the results revealed that 17b induced cell apoptosis and arrested cell cycle in the G2/M phase. Moreover, apoptosis analyses were conducted for compound 17b to evaluate its apoptotic potential. The results showed upregulation in caspase-3 and caspase-9 levels, and improving the Bax/Bcl-2 ratio by more than 10-fold. Docking studies were performed to determine the possible interaction with the VEGFR-2 active site. Further docking studies were carried out for compound 17b against cytochrome P450 to present such compounds as non-inhibitors. In silico ADMET, toxicity, and physico-chemical properties revealed that most of the synthesized members have acceptable values of drug-likeness. Finally, DFT studies were carried out to calculate the thermodynamic, molecular orbital and electrostatic potential properties.

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.

New pyrimidine and pyrazole-based compounds as potential EGFR inhibitors: Synthesis, anticancer, antimicrobial evaluation and computational studies

This study was focused on the synthesis of new pyrimidines 4a,b, 5a,b and pyrazoles 6a, b as ATP mimicking tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR). The new compounds were assessed as cytotoxic candidates against human breast cancer cells (MCF-7) and hepatocellular carcinoma cells (HepG-2). All the new compounds appeared as more potent cytotoxic agents than erlotinib, while only compound 4a exhibited more potency than 5-flourouracil and 4b analogue was equipotent to it. Accordingly, the kinase suppression effect of 4a and 4b was further evaluated against EGFR^WT, EGFR^L858R and EGFR^T790M. Both pyrimidine analogues 4a and 4b displayed outstanding inhibitory activity against EGFR^WT and its two mutated isoforms EGFR^L858R and EGFR^T790M in comparing to erlotinib and osimertinib as reference drugs. Additionally, all the new analogues were subjected to antimicrobial assay. Interestingly, both 4a and 4b represented the most promising activity of wide spectrum antimicrobial effect against the examined microbes in comparison to gentamycin and ketoconazole as standard drugs. Moreover, docking results proved the good binding interactions of the compounds 4a and 4b with EGFR^WT and EGFR^T790M which were in accordance with the results of the in vitro enzyme assay. Additional in silico ADMET studies were performed for the new derivatives which represented their good oral absorption, good drug-likeness properties and low toxicity risks in human.

Synthesis and Molecular Docking of Some Grossgemin Amino Derivatives as Tubulin Inhibitors Targeting Colchicine Binding Site

Six amino derivatives of grossgemin (2–7) were synthesized according to the reported essential pharmacophoric features of colchicine binding site inhibitors (CBSIs). The derivatives 4–6 were obtained for the first time. The pharmacophoric features of 2–7 as CBSIs were studied to be almost identical. Furthermore, the 3D-flexible alignment of compound 5 as a representative example with colchicine showed a very good overlapping. In agreement, compounds 2–7 docked into CBS with binding modes very similar to that of colchicine and exhibited binding free energies of −24.57, −25.05, −32.16, −29.34, −26.38, and −26.86 (kcal/mol), respectively. The binding free energies of 4–7 were better than that of colchicine (−26.13 kcal/mol) with a noticeable superiority to compound 4.

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.

In Vitro and In Silico Cytotoxic and Antibacterial Activities of a Diterpene from Cousinia alata Schrenk

A biologically guided isolation of secondary metabolites from Cousinia alata Schrenk wild plant growing in Akmola region, Kazakhstan, led to the isolation of the bioactive diterpene grindelic acid (1). Six flavonoids were also isolated and identified as retusine (2), pachipodol (3), jaranol (4), penduletin (5), casticin (6), and 5, 7, 3′-trihydroxy-3, 4′-dimethoxyflavone (7). Penduletin (5) showed moderate cytotoxic activity assay. Grindelic acid exhibited promising cytotoxic activity against the Artemia salina nauplii and antibacterial activity against Staphylococcus aureus, Bacillus cereus, and Salmonella enteritidis. The presence of the essential pharmacophoric features of histone deacetylase (HDAC) inhibitors in the structure of grindelic acid encouraged us to run a molecular docking study against the HDAC enzyme to understand its mechanism of action on a molecular level. Grindelic acid showed a binding mode of interaction similar to that of the cocrystallized ligand and exhibited good binding affinity against HDAC with the binding free energy of −18.70 kcal/mol. The structures of isolated compounds were determined by MS, 1D, and 2D NMR spectroscopy methods. Compounds (1–7) were isolated for the first time from Cousinia genus.

Structural modifications on indole and pyrimidine rings of osimertinib lead to high selectivity towards L858R/T790M double mutant enzyme and potent antitumor activity

EGFR inhibitors represent a significant milestone for treatment of non-small cell lung cancer, however, they suffer from the acquired drug resistance. Utilizing osimertinib as the lead compound, this work has explored the structural modifications on the indole and pyrimidine rings of osimertinib to generate novel osimertinib derivatives. The in vitro enzymatic and cellular studies showed that the derivatives possessed high selectivity towards double mutant EGFR and potent antitumor activity. Particularly, compound 6b-1, the most active compound, exhibited excellent inhibitory activity against double mutant EGFR (IC₅₀ = 0.18 nM) and wild-type EGFR (IC₅₀ = 2.89 nM) as well as H1975 cells (IC₅₀ = 1.44 nM). Western blot analysis showed that 6b-1 completely inhibited double mutant EGFR and Erk phosphorylation. In vivo test using xenograft model indicated that compound 6b-1 had better antitumor efficacy than osimertinib. More importantly, 6b-1 displayed many advantages in the pharmacokinetic study, including better oral bioavailability and metabolism character.

Amino Acid Conjugates of Aminothiazole and Aminopyridine as Potential Anticancer Agents: Synthesis, Molecular Docking and in vitro Evaluation

PURPOSE

The development of resistance to available anticancer drugs is increasingly becoming a major challenge and new chemical entities could be unveiled to compensate this therapeutic failure. The current study demonstrated the synthesis of 2-aminothiazole [S3(a-d) and S5(a-d)] and 2-aminopyridine [S4(a-d) and S6(a-d)] derivatives that can target multiple cellular networks implicated in cancer development.

METHODS

Biological assays were performed to investigate the antioxidant and anticancer potential of synthesized compounds. Redox imbalance and oxidative stress are hallmarks of cancer, therefore, synthesized compounds were preliminarily screened for their antioxidant activity using DPPH assay, and further five derivatives S3b, S3c, S4c, S5b, and S6c, with significant antioxidant potential, were selected for investigation of in vitro anticancer potential. The cytotoxic activities were evaluated against the parent (A2780) and cisplatin-resistant (A2780CISR) ovarian cancer cell lines. Further, Molecular docking studies of active compounds were performed to determine binding affinities.

RESULTS

Results revealed that S3c, S5b, and S6c displayed promising inhibition in cisplatin-resistant cell lines in comparison to parent cells in terms of both resistance factor (RF) and IC50 values. Moreover, S3c proved to be most active compound in both parent and resistant cell lines with IC50 values 15.57 µM and 11.52 µM respectively. Our docking studies demonstrated that compounds S3c, S5b, and S6c exhibited significant binding affinity with multiple protein targets of the signaling cascade.

CONCLUSION

Anticancer activities of compounds S3c, S5b, and S6c in cisplatin-resistant cell lines suggested that these ligands may contribute as lead compounds for the development of new anticancer drugs.

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 and molecular modeling of new quinazolin-4(3H)-one based VEGFR-2 kinase inhibitors for potential anticancer evaluation

Globally cancer is the second leading cause of death. So that this work is an attempt to develop new effective anti-cancer agents. In line with pharmacophoric features of VEGFR-2 kinase inhibitors, new nineteen quinazolin-4-one derivatives were designed, synthesized and biologically evaluated for their potential anticancer activity. All target compounds were evaluated in vitro for VEGFR-2 tyrosine kinase inhibition. Then, nine compounds of best results were further investigated by in vitro assay against three human cancer cell lines, namely HepG2, PC3 and MCF. N^'-{2-](3-Ethyl-6-nitro-4-oxo-3,4-dihydroquinazoline-2-yl)thio[acetyl}benzohydrazide (36) was found to be the most potent candidate as it showed IC₅₀ = 4.6 ± 0.06 µM against VEGFR-2 kinase. It also exhibited IC₅₀ = 17.23 ± 1.5, 26.10 ± 2.2 and 30.85 ± 2.3 µg/mL against HepG2, PC3 and MCF, respectively. At the same time it showed IC₅₀ = 145.93 ± 1.1 µg/mL against the normal human lung fibroblasts cell line (WI-38), indicating good selectivity index. Further investigation into HepG2 cell cycle showed the ability of compound 36 to induce apoptosis and arrest cell growth at G2/M phase. Moreover, docking studies demonstrated the ability of compound 36 to bind VEGFR-2 in a correct manner making three essential hydrogen bonds with the key residues Glu885, Asp1046 and Cys919. In sum, this work suggests that compound 36 can serve as a lead for development of effective anticancer agents targeting VEGFR-2.

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.

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.