Design, synthesis, antineoplastic activity of new pyrazolo[3,4-d]pyrimidine derivatives as dual CDK2/GSK3ß kinase inhibitors; molecular docking study, and ADME prediction.

In the current study, novel pyrazolo[3,4-d]pyrimidine derivatives 5a-h were designed and synthesized as targeted anti-cancer agents through dual CDK2/GSK-3ß inhibition. The designed compounds demonstrated moderate to potent activity on the evaluated cancer cell lines (MCF-7 and T-47D). Compounds 5c and 5 g showed the most promising cytotoxic activity against the tested cell lines surpassing that of the used reference standard; staurosporine. On the other hand, both compounds showed good safety and tolerability on normal fibroblast cell line (MCR5). The final compounds 5c and 5 g showed a promising dual CDK2/GSK-3ß inhibitory activity with IC50 of 0.244 and 0.128 µM, respectively, against CDK2, and IC50 of 0.317 and 0.160 µM, respectively, against GSK-3ß. Investigating the effect of compounds 5c and 5 g on CDK2 and GSK-3ß downstream cascades showed that they reduced the relative cellular content of phosphorylated RB1 and ß-catenin compared to that in the untreated MCF-7 cells. Moreover, compounds 5c and 5 g showed a reasonable selective inhibition against the target kinases CDK2/GSK-3ß in comparison to a set of seven off-target kinases. Furthermore, the most potent compound 5 g caused cell cycle arrest at the S phase in MCF-7 cells preventing the cells' progression to G2/M phase inducing cell apoptosis. Molecular docking studies showed that the final pyrazolo[3,4-d]pyrimidine derivatives have analogous binding modes in the target kinases interacting with the hinge region key amino acids. Molecular dynamics simulations confirmed the predicted binding mode by molecular docking. Moreover, in silico predictions indicated their favorable physicochemical and pharmacokinetic properties in addition to their promising cytotoxic activity.

Discovery of novel quinolin-2-one derivatives as potential GSK-3ß inhibitors for treatment of Alzheimer's disease: Pharmacophore-based design, preliminary SAR, in vitro and in vivo biological evaluation.

Recently, glycogen synthase kinase-3ß (GSK-3ß) has been considered as a critical factor implicated in Alzheimer's disease (AD). In a previous work, a 3D pharmacophore model for GSK-3ß inhibitors was created and the results suggested that derivative ZINC67773573, VIII, may provide a promising lead for developing novel GSK-3ß inhibitors for the AD's treatment. Consequently, in this work, novel series of quinolin-2-one derivatives were synthesized and assessed for their GSK-3ß inhibitory properties. In vitro screening identified three compounds: 7c, 7e and 7f as promising GSK-3ß inhibitors. Compounds 7c, 7e and 7f were found to exhibit superior inhibitory effect on GSK-3ß with IC50 value ranges between 4.68 ± 0.59 to 8.27 ± 0.60 nM compared to that of staurosporine (IC50 = 6.12 ± 0.74 nM). Considerably, compounds 7c, 7e and 7f effectively lowered tau hyperphosphorylated aggregates and proving their safety towards the SH-SY5Y and THLE2 normal cell lines. The most promising compound 7c alleviated cognitive impairments in the scopolamine-induced model in mice. Compound 7c's activity profile, while not highly selective, may provide a starting point and valuable insights into the design of multi-target inhibitors. According to the ADME prediction results, compounds 7c, 7e and 7f followed Lipinski's rule of five and could almost permeate through the BBB. Molecular docking simulations showed that these compounds are well accommodated in the ATP binding site interacting by its quinoline-2-one ring through hydrogen bonding with the key amino acids Asp133 and Val135 at the hinge region. The findings of this study suggested that these new compounds may have potential as anti-AD drugs targeting GSK-3ß.

Benzimidazole-oxindole hybrids as multi-kinase inhibitors targeting melanoma.

In the current study, a series of benzimidazole-oxindole conjugates 8a-t were designed and synthesized as type II multi-kinase inhibitors. They exhibited moderate to potent inhibitory activity against BRAFWT up to 99.61 % at 10 µM. Notably, compounds 8e, 8k, 8n and 8s demonstrated the most promising activity, with 99.44 to 99.61 % inhibition. Further evaluation revealed that 8e, 8k, 8n and 8s exhibit moderate to potent inhibitory effects on the kinases BRAFV600E, VEGFR-2, and FGFR-1. Additionally, compounds 8a-t were screened for their cytotoxicity by the NCI, and several compounds showed significant growth inhibition in diverse cancer cell lines. Compound 8e stood out with a GI50 range of 1.23 - 3.38 µM on melanoma cell lines. Encouraged by its efficacy, it was further investigated for its antitumor activity and mechanism of action, using sorafenib as a reference standard. The hybrid compound 8e exhibited potent cellular-level suppression of BRAFWT, VEGFR-2, and FGFR-1 in A375 cell line, surpassing the effects of sorafenib. In vivo studies demonstrate that 8e significantly inhibits the growth of B16F10 tumors in mice, leading to increased survival rates and histopathological tumor regression. Furthermore, 8e reduces angiogenesis markers, mRNA expression levels of VEGFR-2 and FGFR-1, and production of growth factors. It also downregulated Notch1 protein expression and decreased TGF-ß1 production. Molecular docking simulations suggest that 8e binds as a promising type II kinase inhibitor in the target kinases interacting with the key regions in their kinase domain.

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

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

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

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

Discovery of dual rho-associated protein kinase 1 (ROCK1)/apoptosis signal-regulating kinase 1 (ASK1) inhibitors as a novel approach for non-alcoholic steatohepatitis (NASH) treatment.

In the current study we suggest a novel approach to curb non-alcoholic steatohepatitis (NASH) progression, and we suggest privileged scaffolds for the design of novel compounds for this aim. NASH is an advanced form of non-alcoholic fatty liver disease that can further progress into fibrosis, cirrhosis, and hepatocellular carcinoma. It is a widely emerging disease affecting 25% of the global population and has no current approved treatments. Protein kinases are key regulators of cellular pathways, of which, Rho-associated protein kinase 1 (ROCK1) and apoptosis signal-regulating kinase 1 (ASK1) play an important role in the progression of NASH and they stand out as promising targets for NASH therapy. Interestingly, their kinase domains are found to be similar in sequence and topology; therefore, dual inhibition of ROCK1 and ASK1 is expected to be amenable and could achieve a more favourable outcome. To reach this goal, a training set of ROCK1 and ASK1 protein structures co-crystalized with type 1 (ATP-competitive) inhibitors was constructed to manually generate receptor-based pharmacophore models representing ROCK1 and ASK1 inhibitors' common pharmacophoric features. The models produced were assessed using a test set of both ROCK1 and ASK1 actives and decoys, and their performance was evaluated using different assessment metrics. The best pharmacophore model obtained, showing a Mathew's correlation coefficient (MCC) of 0.71, was then used to screen the ZINC purchasable database retrieving 6178 hits that were filtered accordingly using several medicinal chemistry and pharmacokinetics filters returning 407 promising compounds. To confirm that these compounds are capable of binding to the target kinases, they were subjected to molecular docking simulations at both protein structures. The results were then assessed individually and filtered, setting the spotlight on various privileged scaffolds that could be exploited as the nucleus for designing novel ROCK1/ASK1 dual inhibitors.

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

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

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

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

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

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

New quinazolinone-based derivatives as DHFR/EGFR-TK inhibitors: Synthesis, molecular modeling simulations, and anticancer activity.

New 2-mercapto-quinazolin-4-one analogs were synthesized and tested for their in vitro anticancer activity, dihydrofolate reductase (DHFR) inhibition, and epidermal growth factor tyrosine kinase (EGFR-TK) inhibition activities. Compound 24, which is characterized by a 2-benzyl-thio function, showed broad-spectrum anticancer activity with high safety profile and selectivity index. The concentrations of 24 causing 50% growth inhibition (GI50 ) and total cell growth inhibition (TGI) and its lethal concentration 50 (LC50 ) were 15.1, 52.5, and 91.2 µM, respectively, using 5-fluorouracil as a positive control. Also, it showed EGFR-TK inhibitory activity with IC50 = 13.40 nM compared to gefitinib (IC50 = 18.14 nM) and DHFR inhibitory potency with 0.30 µM compared to methotrexate (MTX; IC50 = 0.08 µM). In addition, compound 24 caused cell cycle arrest and apoptosis on COLO-205 colon cancer cells. Compounds 37, 21, and 54 showed remarkable DHFR inhibitory activity with IC50 values of 0.03, 0.08, and 0.08 µM, respectively. The inhibitory properties of these compounds are due to an electron-withdrawing group on the quinazolinone ring, except for compound 54. In a molecular modeling study, compound 24 showed the same binding mode as gefitinib as it interacted with the amino acid Lys745 via π-π interaction. Compound 37 showed a similar binding mode as MTX through the binding interaction with Lys68, Asn64 via hydrogen bond acceptor, and Phe31 via arene-arene interaction. The obtained model and substitution pattern could be used for further development.

A Perspective Study on the RTK, PI3K, B-Raf, CDK and the Multi-Protein Targeting in Medicinal Chemistry.

The cellular signaling pathway components that control the different stages of cell maturation such as RTK, PI3K, B-Raf, and CDK represent crucial antitumor drug targets. The isoform diversity of these components revealed multi-divergent vents for cancer cells to develop several resistance mechanisms against these new selective drug targets. This review article illustrates the complex nature of cancer, moreover, molecular tracing of tumor resistance towards certain signaling pathways was presented. Several crucial interventions in this regard for antitumor agents' development were pointed out. The antitumor activities of several cancer chemotherapies targeting kinases were also discussed with a special focus on the structural bases for the design of protein kinase inhibitors. Additionally, a focused literature survey about the various targeted multi-kinase inhibition approaches as a mean to overcome cancer resistance was also included.

Design, synthesis and anticancer activity of novel 2-arylbenzimidazole/2-thiopyrimidines and 2-thioquinazolin-4(3H)-ones conjugates as targeted RAF and VEGFR-2 kinases inhibitors.

In the current study, series of 2-arylbenzimidazole-thiopyrimidine and -thioquinazolin-4(3H)-ones conjugates 12a-d, 13a,b and 14a-l have been synthesized. All the synthesized compounds were tested in vitro for their anticancer activities against a panel of cancer cell lines at NCI - US and their growth inhibition (GI) % were determined at 10 µM. Compounds 14c and 14g-i were selected to be screened at the five dose assay and were found to exhibit GI50 values 1.1-30.0 µM. The benzimidazole-quinazolinone derivative 14c, in particular, showed potent anticancer activity against the tested cancer cell lines (GI50 of 1.3-4.2 µM). In addition, compounds 12a,b, 13a, 14a-e, 14g, 14i and 14j were selected to be tested against some cancer cell lines using MTT assay and the benzimidazole-quinazolinone 14g was found to have potent anticancer activities against melanoma (Mel-501 and A-375), breast (MCF-7), colon (HCT-116), prostate (PC-3), lung (A-549) and pancreas (Paca-2) cancer cell lines reporting IC50 values ranging between 0.1 and 6.2 µM. Moreover, the synthesized hybrids were tested in vitro on kinases; BRAF (wt), BRAF (V600E), CRAF and VEGFR-2. The benzimidazole-quinazolinone derivatives 14f,g revealed potent RAF kinases inhibitory activities on BRAF (wt), BRAF (V600E) and CRAF showing IC50 values 0.002-0.1 µM, whereas, the benzimidazole-quinazolinone derivatives 14i and 14k showed moderate VEGFR-2 inhibitory activity (IC50 = 20.60 and 6.14 µM, respectively). Moreover, the representative compounds 14g and 14i caused cell cycle arrest of A-375 melanoma cell line at G2/M phase and were found to induce late apoptosis. CRAF in the DFG-out inactive conformation homology modeling was first reported in this study and molecular docking studies on BRAF, CRAF and VEGFR-2 were also performed to investigate the binding modes of the target compounds and their interactions with the key amino acids; BRAF (Glu500, Cys531 and Asp593), CRAF (Glu393, Cys424 and Asp486) and VEGFR-2 (Glu885, Cys919 and Asp1046).

Novel 2-(5-Aryl-4,5-Dihydropyrazol-1-yl)thiazol-4-One as EGFR Inhibitors: Synthesis, Biological Assessment and Molecular Docking Insights.

Introduction: Epidermal growth factor receptor (EGFR) regulates several cell functions which include cell growth, survival, multiplication, differentiation, and apoptosis. Currently, EGFR kinase inhibitors are of increasing interest as promising targeted antitumor therapeutic agents. Methods: Different thiazolyl-pyrazoline derivatives (7a-o) were synthesized and were first tested for anti-proliferative effect towards the A549 lung cancer cell line and the T-47D breast cancer cell line in MTT assay. Thereafter, thiazolyl-pyrazolines (7b, 7g, 7l, and 7m) were subsequently evaluated for their PK inhibition for EGFR. Moreover, representative promising derivatives (7g and 7m) in cytotoxic and PK inhibition assays were tested to investigate their impact on the apoptosis and cell cycle phases in T-47D cells in order to explore more insights into the antitumor actions of the target thiazolyl-pyrazolines. Furthermore, docking studies were accomplished to evaluate the patterns of binding of thiazolyl-pyrazolines 7b, 7g, 7l, and 7m in the EGFR active pocket (PDB ID: 1M17). Results: Testing the thiazolyl pyrazoline compounds 7a-o on A549 and T-47D cell lines showed IC50 arrays between 3.92 and 89.03 µM, and between 0.75 and 77.10 µM, respectively. Also, the tested thiazolyl-pyrazolines (7b, 7g, 7l, and 7m) demonstrated significant sub-micromolar EGFR inhibitory actions with IC50 values 83, 262, 171 and 305 nM, respectively, in comparison to erlotinib (IC50 =57 nM). Discussion: Generally, it was observed that the tested thiazolyl pyrazolines showed more potent antiproliferative activity toward breast cancer cells T-47D than toward lung cancer cell lines A549. In particular, thiazolyl pyrazolines 7g and 7m showed the best activity against A549 cells (IC50 = 3.92 and 6.53 µM) and T-47D cells (IC50 = 0.88 and 0.75 µM). Compounds 7g and 7m provoked a sub-G1 phase arrest and cell apoptosis which are in agreement with the expected outcome of EGFR inhibition. Finally, the molecular docking of 7g and 7m in the active site of EGFR revealed a common binding pattern similar to that of erlotinib which involves the accommodation of the 1,3 thiazol-4-one ring and pyrazoline ring of target compounds in the binding region of erlotinib's quinazoline ring and anilino moiety.

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

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

Novel benzothiazole-based dual VEGFR-2/EGFR inhibitors targeting breast and liver cancers: Synthesis, cytotoxic activity, QSAR and molecular docking studies.

A novel series of benzothiazole-based derivatives linked to various amino acids and their corresponding ethyl ester analogues were prepared and were initially evaluated for their anticancer activity againstMCF-7 and HepG-2 and were further assessed as VEGFR-2 inhibitors. All the newly synthesized benzothiazole derivatives showed promising cytotoxic activities against the tested cell lines. Derivatives exhibited potent cytotoxic and VEGFR-2 inhibitory activities were then evaluated further as anticancer agents against the resistant MDA-MB-231 and as EGFR inhibitors. The carboxylic acid derivatives 10-12 and their ester analogues 21-23 displayed the highest anticancer activities with IC50 of 0.73-0.89 µM, against MCF-7 and IC50 of 2.54-2.80 µM, against HepG-2; compared to doxorubicin (IC50 = 1.13 and 2.75 µM, respectively); also they showed safety towards the normal cell line, the ethyl ester derivatives 21-23 showed a potent activity against the resistant MDA-MB-231 cell line with IC50 of 5.45-7.28 µM, relative to doxorubicin (IC50 = 7.46 µM) surpassing their carboxylic acid analogues 10-12 (IC50 of 8.88-11.02 µM). Furthermore, the promising derivatives 10-12 and 21-23 displayed promising VEGFR-2 inhibitory activity (IC50 = 0.15-0.19 µM) comparable to that of sorafenib (IC50 = 0.12 µM). Against EGFR, the ethyl ester derivatives 21-23 showed superior inhibitory activity relative to the used reference standard, erlotinib, with IC50 of 0.11-0.16 vs. 0.18 µM, respectively. The QSAR study revealed that the molecular bulkiness and molecular partial charge distribution govern the kinase inhibition potency in this series. Furthermore, the molecular docking study in VEGFR-2 active site showed that the novel synthesized benzothiazole derivatives adopted the common binding pattern of type II PK inhibitors.

Application of the dual-tail approach for the design and synthesis of novel Thiopyrimidine-Benzenesulfonamide hybrids as selective carbonic anhydrase inhibitors.

A dual-tail approach was applied to the design of a novel series of 2-thiopyrimidine-benzenesulfonamides as carbonic anhydrase (CA) inhibitors. The design strategy is based on the hybridization between a benzenesulfonamide moiety as Zn2+ binding group and 2,4-disubstituted thiopyridimidine as a tail. Among the synthesized compounds, 14h displayed the highest potency (Ki = 1.72 nM) and selectivity for CA II over the isoforms CA IX and CA XII with selectivity indexes of 50 and 5.26, respectively. Meanwhile, compounds 14a and 14l displayed a potent inhibitory activity against CA IX (Ki = 7.4 and 7.0 nM, respectively) compared with the reference drug acetazolamide (AAZ) (Ki = 25 nM), and compound 14l showed higher potency (Ki = 4.67 nM) than AAZ (Ki = 5.7 nM) against the tumor-associated isoform CA XII. Evaluation of the antiproliferative activity in NCI single-dose testing of selected hybrids revealed a pronounced potency of the selective CA II inhibitor 14h against most of the tested NCI cancer cell lines. Moreover, compound 14h demonstrated an IC50 values ranging from 2.40 to 4.50 µM against MCF-7, T-47D, MDA-MB-231, HCT-116, HT29 and SW-620. These results demonstrate that CA II inhibition can be an alternative therapeutic target for cancer treatment. A cell cycle analysis of MCF-7 and MDA-MB-231 showed that treatment with 14h arrested both cell lines at the G2/M phase with significant accumulation of cells in the pre-G1 phase. Moreover, compound 14h showed a noticeable induction of late apoptosis and necrotic cell death of both cell lines compared with untreated cells as a control. A molecular docking study suggested that the sulfonamide moiety accommodates deeply in the CA active site and interacts with the Zn2+ ion while the dual-tail extension interacts with the surrounding amino acids via several hydrophilic and hydrophobic interactions, which affects the potency and selectivity of the hybrids.

Design, synthesis and in silico insights of new 7,8-disubstituted-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione derivatives with potent anticancer and multi-kinase inhibitory activities.

Aiming to obtain an efficient anti-proliferative activity, structure- and ligand-based drug design approaches were expanded and utilized to design and refine a small compound library. Subsequently, thirty-two 7,8-disubstituted-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione derivatives were selected for synthesis based on the characteristic pharmacophoric features required for PI3K and B-Raf oncogenes inhibition. All the synthesized compounds were evaluated for their in vitro anticancer activity. Compounds 17 and 22c displayed an acceptable potent activity according to the DTP-NCI and were further evaluated in the NCI five doses assay. To validate our design, compounds with the highest mean growth inhibition percent were screened against the target PI3Kα and B-RafV600E to confirm their multi-kinase activity. The tested compounds showed promising multi-kinase activity. Compounds 17 and 22c anticancer effectiveness and multi-kinase activity against PI3Kα and B-RafV600E were consolidated by the inhibition of B-RafWT, EGFR and VEGFR-2 with IC50 in the sub-micromolar range. Further investigations on the most potent compounds 17 and 22c were carried out by studying their safety on normal cell line, in silico profiling and predicted ADME characteristics.

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

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

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

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

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

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