Design, synthesis, and antitumor activity of novel compounds based on 1,2,4-triazolophthalazine scaffold: Apoptosis-inductive and PCAF-inhibitory effects

Rationale, in silico docking, ADMET profile, design, synthesis and cytotoxicity evaluations of phthalazine derivatives as VEGFR-2 inhibitors and apoptosis inducers

New phthalazine derivatives as vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitors were synthesized joined to different spacers including pyrazole, α,β-unsaturated ketonic fragment, pyrimidinone and/or pyrimidinthione. A docking study was carried out to explore the suggested binding orientations of the novel derivatives inside the active site of VEGFR-2. The obtained biological data were extremely interrelated to that of the docking study. In particular, compounds 4b and 3e showed the highest activities against Michigan Cancer Foundation-7 (MCF-7) and Hepatocellular carcinoma G2 (HepG2) with half maximal inhibitory concentration (IC50) = 0.06, 0.06 μM and 0.08, 0.19 μM respectively. Our derivatives 3a-e, 4a,b and 5a,b were evaluated for their cytotoxicity against normal VERO cells. Our compounds exhibited low toxicity concerning normal VERO cells with IC50 = 3.00-4.75 μM. In addition, our final derivatives 3a-e, 4a, 4b, 5a and 5b were investigated for their VEGFR-2 inhibitory activities. Derivative 4b exhibited the highest VEGFR-2 inhibitory activities at an IC50 value of 0.09 ± 0.02 μM. Derivatives 3e, 4a and 5b demonstrated good activities with IC50 values = 0.12 ± 0.02, 0.15 ± 0.03 and 0.13 ± 0.03 μM respectively. Furthermore, the activities of 4b were assessed against MCF-7 cancer cells for apoptosis induction, cell cycle distribution and growth inhibition. Compound 4b caused cell growth arrest in growth 2-mitosis (G2-M) phase; accumulation of cells at that phase became 6.92% after being 13.2 in control cells. Moreover, our derivatives 3e, 4b and 5b revealed a good in silico considered absorption, distribution, metabolism, excretion, and toxicity (ADMET) profile in comparison to sorafenib.

Synthesis, enzyme inhibition assay, and molecular modeling study of novel pyrazolines linked to 4-methylsulfonylphenyl scaffold: antitumor activity and cell cycle analysis

Antitumor activity using 59 cancer cell lines and enzyme inhibitory activity of a newly synthesized pyrazoline-linked 4-methylsulfonylphenyl scaffold (compounds 18a-q) were measured and compared with those of standard drugs. Pyrazolines 18b, 18c, 18f, 18g, 18h, and 18n possessed significant antitumor activity, with a positive cytotoxic effect (PCE) of 22/59, 21/59, 21/59, 48/59, 51/59, and 20/59, respectively. The cancer cell lines HL60, MCF-7, and MDA-MB-231 were used to measure the IC50 values of derivatives 18c, 18g, and 18hvia the MTT assay method, and the results were compared with those of reference drugs. Derivatives 18g and 18h showed potent and broad-spectrum antitumor activities against HL60 (IC50 of 10.43, 8.99 μM, respectively), MCF-7 (IC50 of 11.7 and 12.4 μM, respectively), and MDA-MB-231 (IC50 of 4.07 and 7.18 μM, respectively). Compound 18c exhibited strong antitumor activity against HL60 and MDA-MB-231 cell lines with IC50 values of 8.43 and 12.54 μM, respectively, and moderate antitumor activity against MCF-7 cell lines with an IC50 value of 16.20 μM. Compounds 18c, 18g, and 18h remarkably inhibited VEGFR2 kinase (IC50 = 0.218, 0.168, and 0.135 μM, respectively) compared with the reference drug sorafenib (IC50 = 0.041 μM). Compounds 18g and 18h effectively inhibited HER2 kinase (IC50 = 0.496 and 0.253 μM, respectively) compared with erlotinib (IC50 = 0.085 μM). Compound 18h inhibited EGFR kinase (IC50 = 0.574 μM) with a potency comparable with that of the reference drug erlotinib (IC50 = 0.105 μM). Pyrazolines 18c, 18f, and 18h arrested the S/G2 phase of the cell cycle in HL-60 cells. In addition, derivatives 18c, 18f, and 18h revealed lower Bcl-2 protein expression anti-apoptotic levels and higher Bax, caspase-3, and caspase-9 expression levels. Molecular docking studies of derivative 18h into the binding sites of EGFR, HER2, and VEGFR2 kinases explored the interaction mode of these pyrazoline derivatives and their structural requirements for antitumor activity.

Exploration of the VEGFR-2 inhibition activity of phthalazine derivatives: design, synthesis, cytotoxicity, ADMET, molecular docking and dynamic simulation

Novel phthalazine derivatives were designed, synthesized and evaluated against Hep G2 and MCF-7 as VEGFR-2 inhibitors. In particular, compounds 2g and 4a were found to be the most potent derivatives among all the tested compounds against MCF-7 and Hep G2 cancer cell lines with IC50 values of 0.15 and 0.12 and 0.18 and 0.09 μM respectively. Moreover, compounds 3a, 3c, 5a and 5b displayed excellent anticancer activities against MCF-7 and Hep G2 cancer cell lines. The highly active derivatives 2g, 3a, 3c, 4a, 5a and 5b were evaluated for their inhibitory activities against VEGFR-2. The tested compounds displayed high to low inhibitory activities with IC50 values ranging from 0.148 to 0.892 μM. Among them, compounds 2g and 4a were found to be the most potent derivatives that inhibited VEGFR-2 with IC50 values of 0.148 and 0.196 μM respectively. Compounds 3a, 3c, 5a and 5b exhibited good activity with IC50 values of 0.375, 0.892, 0.548 and 0.331 μM respectively. Sorafenib was used as a reference drug in this study. Molecular modeling studies were carried out for all compounds against the VEGFR-2 active site. The data obtained from biological testing highly correlated with those obtained from molecular modeling studies. Moreover, MD simulation results indicated the stability of ligand-target interaction. Furthermore, our derivatives 2g and 4a showed a good in silico calculated ADMET profile.

Design, synthesis and mechanistic study of new dual targeting HDAC/tubulin inhibitors

Aim: The purpose of this work is to create and synthesize a new class of chemicals: 3-cyano-2-substituted pyridine compounds with expected multitarget inhibition of histone deacetylase (HDAC) and tubulin. Materials & methods: The target compounds (3a-c, 4a-c and 5a-c) were synthesized utilizing 6-(4-methoxyphenyl)-2-oxo-4-(3,4,5-trimethoxyphenyl)-3-cyanopyridine, with various linkers and zinc-binding groups (ZBGs). Results: Most of the tested compounds showed promising growth inhibition, and hydroxamic acid-containing hybrids possessed higher HDAC inhibition than other ZBGs. Compound 4b possessed the highest potency; however, it showed the most tubulin polymerization inhibition. Docking studies displayed good binding into HDAC1 and six pockets and tubulin polymerization protein. Conclusion: Compound 4b could be considered a good antitumor candidate to go further into in vivo and clinical studies.

Androgen receptor cofactors: A potential role in understanding prostate cancer

Prostate cancer (PCa) is witnessing a concerning rise in incidence annually, with the androgen receptor (AR) emerging as a pivotal contributor to its growth and progression. Mounting evidence underscores the AR's ability to recruit cofactors, influencing downstream gene transcription and thereby fueling the proliferation and metastasis of PCa cells. Although, clinical strategies involving AR antagonists provide some relief, managing castration resistant prostate cancer (CRPC) remains a formidable challenge. Thus, the need of the hour lies in unearthing new drugs or therapeutic targets to effectively combat PCa. This review encapsulates the pivotal roles played by coactivators and corepressors of AR, notably androgen receptor-associated protein (ARA) and steroid receptor Coactivators (SRC) in PCa. Our data unveils how these cofactors intricately modulate histone modifications, cell cycling, SUMOylation, and apoptosis through their interactions with AR. Among the array of cofactors scrutinised, such as ARA70β, ARA24, ARA160, ARA55, ARA54, PIAS1, PIAS3, SRC1, SRC2, SRC3, PCAF, p300/CBP, MED1, and CARM1, several exhibit upregulation in PCa. Conversely, other cofactors like ARA70α, PIASy, and NCoR/SMRT demonstrate downregulation. This duality underscores the complexity of AR cofactor dynamics in PCa. Based on our findings, we propose that manipulating cofactor regulation to modulate AR function holds promise as a novel therapeutic avenue against advanced PCa. This paradigm shift offers renewed hope in the quest for effective treatments in the face of CRPC's formidable challenges.

New antiproliferative 3-substituted oxindoles inhibiting EGFR/VEGFR-2 and tubulin polymerization

New 3-substituted oxindole derivatives were designed and synthesized as antiproliferative agents. The antiproliferative activity of compounds 6a-j was evaluated against 60 NCI cell lines. Among these tested compounds, compounds 6f and 6g showed remarkable antiproliferative activity, specifically against leukemia and breast cancer cell lines. Compound 6f was the most promising antiproliferative agent against MCF-7 (human breast cancer) with an IC50 value of 14.77 µM compared to 5-fluorouracil (5FU) (IC50 = 2.02 µM). Notably, compound 6f hampered receptor tyrosine EGFR fundamentally with an IC50 value of 1.38 µM, compared to the reference sunitinib with an IC50 value of 0.08 µM. Moreover, compound 6f afforded anti-tubulin polymerization activity with an IC50 value of 7.99 µM as an outstanding observable activity compared with the reference combretastatin A4 with an IC50 value of 2.64 µM. In silico molecular-docking results of compound 6f in the ATP-binding site of EGFR agreed with the in vitro results. Besides, the investigation of the physicochemical properties of compound 6f via the egg-boiled method clarified good lipophilicity, GIT absorption, and blood-brain barrier penetration properties.

Novel benzochromenes: design, synthesis, cytotoxicity, molecular docking and mechanistic investigations

Aim: A novel series of fused benzochromenes with expected cytotoxicity and HIF-1α inhibition was identified. Materials & methods: A bioisosterism-aided approach was applied to design new benzochromenes and assess their cytotoxicity against three cancer cell lines. The probable mechanistic effect and the in silico docking and pharmacokinetic profiles of the most effective derivatives were evaluated. Results: Compounds 3, 4, 5, 8 and 11 showed potent antiproliferative activity and excellent selectivity. Compound 8 showed significant HIF-1α inhibition with an IC50 value of 3.372 μM. It also enhanced apoptosis and arrested the HepG2 cell cycle at both the G0/G1 and S stages. Conclusion: Compound 8 was identified as a new potential anticancer candidate.

Aminopyridone-linked benzimidazoles: a fragment-based drug design for the development of CDK9 inhibitors

Aim: A fragment-based design and synthesis of three novel series of aminopyridone-linked benzimidazoles as potential anticancer candidates with significant CDK9 inhibition was implemented. Materials & methods: All synthesized compounds were submitted to National Cancer Institute, 60 cell lines and seven-dose cytotoxicity toward three cancer cells. Results: Compounds 2, 4a, 4c, 4d, 6a and 8a exhibited significant cytotoxicity and selectivity with IC50 range of 7.61-57.75 μM. Regarding the mechanism either in vitro or in silico, 4a, 6a and 8a displayed potent CDK9 inhibition with IC50 value of 0.424-8.461 μM. Compound 6a arrested the cell cycle at S phase and induced apoptosis in MCF-7 cells. Conclusion: Compound 6a is a promising CDK9 inhibitor that warrants additional research for cancer treatment.

Design and synthesis of novel uracil-linked Schiff bases as dual histone deacetylase type II/topoisomerase type I inhibitors with apoptotic potential

Aim: The previously reported dual histone deacetylase type II (HDAC II) / topoisomerase type I (Topo I) inhibitors suffer pharmacokinetic limitations because of their huge molecular weights. Materials & methods: We report the design and synthesis of a smarter novel set of uracil-linked Schiff bases (19-30) as dual HDAC II/Topo I inhibitors keeping the essential pharmacophoric features. Cytotoxicity of all compounds was assessed against three cancer cell lines. Studies of their effects on the apoptotic BAX and antiapoptotic BCL2 genes, molecular docking studies, and absorption, distribution, metabolism and excretion studies were conducted. Results: Compounds 22, 25 and 30 exhibited significant activities. The bromophenyl derivative 22 displayed the best selectivity index, with IC50 values against HDAC II and Topo I of 1.12 and 13.44 μM, respectively. Conclusion: Compound 22 could be considered a lead HDAC II/Topo I inhibitor.

New benzothienopyran and benzothienopyranopyrimidine derivatives as topoisomerase I inhibitors: Design, synthesis, anticancer screening, apoptosis induction and molecular modeling studies

New benzothienopyran and benzothienopyranopyrimidine derivatives were synthesized based on the structural requirements of topoisomerase I inhibitors. All target compounds exhibited strong cytotoxic activity with GI₅₀ range of 70.62 %-87.29 % in one dose NCI (USA) screening against 60 human tumor cell lines. Among the tested derivatives, eight compounds namely 4d, 4e, 4f, 5b, 5e, 6b, 6d, and 6f demonstrated broad spectrum and potent anticancer efficacy in five dose screening against all tested panels. DNA relaxation assay for the latter compounds showed that 4d, 5b, and 6f exhibited excellent inhibitory activity with IC₅₀ range of 2.553-4.495 µM as compared to indenoisoquinoline reference drug (IC₅₀ = 3.911 ± 0.21 µM). Moreover, the most active compounds were investigated for being topoisomerase poisons or catalytic inhibitors using DNA nicking assay. Compounds 4d and 6f were found to be potential Topo I poisons, whereas compound 5b has acted as Topo I suppressor. Analyzing cell cycle and induction of apoptosis for the most active compound 4d, revealed growth arrest at the S phase in MDA-MB-435 cells similarly to indenoisoquinoline reference drug. Additionally, in silico molecular modeling study for eight most active cytotoxic compounds in five dose screening demonstrated interaction with DNA as well as distinctive binding pattern similar to the reference indenoisoquinoline, indicating that the newly discovered targets are supposed to be promising candidates as Topo I inhibitors.

Exploring the cytotoxic effect and CDK-9 inhibition potential of novel sulfaguanidine-based azopyrazolidine-3,5-diones and 3,5-diaminoazopyrazoles

Regarding the structural analysis of variable effective CDK-9 suppressors, we record the design and synthesis of two new sets of sulfaguanidine-based azopyrazolidine-3,5-diones and 3,5-diaminoazopyrazoles with expected anticancer and CDK-9 inhibiting activity. In the designed molecules, the pyrazole ring and sulphaguanidine fragment were linked together for the first time through diazo linkers as they are expected to enhance the anticancer activity and CDK degrading interaction. All derivatives have been estimated regarding their cytotoxic activity toward three tumor cells where CDK overexpression has been reported (HePG2, HCT-116, and MCF-7). Among these, four derivatives VII, VIII, X, and XIII exerted potent cytotoxicity against the chosen tumor cells presenting IC₅₀ range equal to 2.86-25.89 µM. As well cytotoxicity on non-cancer cells and CDK-9 inhibition assay have been also assessed for these candidates to evaluate their selectivity indices and enzyme inhibition. The 3,5-diaminopyrazole-1-carboxamide derivative XIII showed a superior combined profile as cytotoxic with high selectivity toward cancer cells (HePG2: IC₅₀ = 6.57 µM, SI = 13.31; HCT-116: IC₅₀ = 9.54 µM, SI = 9.16; MCF-7: IC₅₀ = 7.97 µM, SI = 10.97). Accordingly, it has been chosen to evaluate its probable mechanistic effect both in vitro (via enzyme assay, apoptosis induction, and cell cycle study) as well as in silico (through molecular docking). Overall, this work introduces the 3,5-diaminopyrazole-1-carboxamide derivative XIII as a potent CDK-9 inhibitor candidate (IC₅₀ = 0.16 µM) that merits further investigations for the management of breast, colorectal, and hepatic malignancies.

A novel class of phenylpyrazolone-sulphonamides rigid synthetic anticancer molecules selectively inhibit the isoform IX of carbonic anhydrases guided by molecular docking and orbital analyses

All the previously reported phenylpyrazoles as carbonic anhydrase inhibitors (CAIs) were found to have small sizes and high levels of flexibility, and hence showed low selectivity profiles toward a particular isoform of CA. Herein, we report the development of a more rigid ring system bearing a sulfonamide hydrophilic head and a lipophilic tail to develop novel molecules that are suggested to have a better selectivity toward a special CA isoform. Accordingly, three novel sets of pyrano[2,3-c]pyrazoles attached with sulfonamide head and aryl hydrophobic tail were synthesized to enhance the selectivity toward a specific isoform of human carbonic anhydrases (hCAs). The impact of both attachments on the potency and selectivity has been extensively discussed in terms of in vitro cytotoxicity evaluation under hypoxic conditions, structure-activity relationship and carbonic anhydrase enzyme assay. All of the new candidates displayed good cytotoxic activities against breast and colorectal carcinomas. Results of the carbonic anhydrase enzyme assay demonstrated the preferential of compounds 22, 24 and 27 to inhibit the isoform IX of hCAs selectively. Wound-healing assay has also been performed and revealed the potential of 27 to decrease the wound closure percentage in MCF-7 cells. Molecular docking and molecular orbital analysis have finally been conducted. Results indicate the potential binding interactions of 24 and 27 with several crucial amino acids of the hCA IX.Communicated by Ramaswamy H. Sarma.

Recent Advances on Small-Molecule Bromodomain-Containing Histone Acetyltransferase Inhibitors

In recent years, substantial research has been conducted on molecular mechanisms and inhibitors targeting bromodomains (BRDs) and extra-terminal (BET) family proteins. On this basis, non-BET BRD is gradually becoming a research hot spot. BRDs are abundant in histone acetyltransferase (HAT)-associated activating transcription factors, and BRD-containing HATs have been linked to cancer, inflammation, and viral replication. Therefore, the development of BRD-containing HATs as chemical probes is useful for understanding the specific biological roles of BRDs in diseases and drug discovery. Several types of BRD-containing HATs, including CBP/P300, PCAF/GCN5, and TAF1, are discussed in this context in terms of their structures, functions, and small-molecule inhibitors. Additionally, progress in BRD inhibitors/chemical probes and proteolysis targeting chimeras in terms of drug design, biological activity, and disease application are summarized. These findings provide insights into the development of BRD inhibitors as potential drug candidates for various diseases.

The anticancer and EGFR-TK/CDK-9 dual inhibitory potentials of new synthetic pyranopyrazole and pyrazolone derivatives: X-ray crystallography, in vitro, and in silico mechanistic investigations

Treatment options for the management of breast cancer are still inadequate. This inadequacy is attributed to the lack of effective targeted medications, often resulting in the recurrence of metastatic disorders. Cumulative evidence suggests that epidermal growth factor receptor (EGFR-TK) and cyclin-dependent kinases-9 (CDK-9) overexpression correlates with worse overall survival in breast cancer patients. Pyranopyrazole and pyrazolone are privileged options for the development of anticancer agents. Inspired by this proven scientific fact, we report here the synthesis of two new series of suggested anticancer molecules incorporating both heterocycles together with their characterization by IR, 1H NMR, 13C NMR, 13C NMR-DEPT, and X-ray diffraction methods. An attempt to get the pyranopyrazole-gold complexes was conducted but unexpectedly yielded benzylidene-2,4-dihydro-3H-pyrazol-3-one instead. This unexpected result was confirmed by X-ray crystallographic analysis. All newly synthesized compounds were assessed for their anti-proliferative activity against two different human breast cancer cells, and the obtained results were compared with the reference drug Staurosporine. The target compounds revealed variable cytotoxicity with IC50 at a low micromolar range with superior selectivity indices. Target enzyme EGFR-TK and CDK-9 assays showed that compounds 22 and 23 effectively inhibited both biological targets with IC50 values of 0.143 and 0.121 µM, respectively. Molecular docking experiments and molecular dynamics simulation were also conducted to further rationalize the in vitro obtained results.Communicated by Ramaswamy H. Sarma.

New pyrazole-tetrazole hybrid compounds as potent α-amylase and non-enzymatic glycation inhibitors

The synthesis of eight novel pyrazole-tetrazole compounds are presented. Their structures are identified by NMR and FTIR spectroscopy, mass spectrometry as well as elemental analysis. Their in-vitro α-amylase inhibition and haemoglobin antiglycation activity were examined by spectrophotometric methods. All compounds possess both activities, especially molecules entitled 2-(1-((5-methyl-1H-pyrazol-3-yl)methyl)-1H-tetrazol-5-yl)pyridine 4 and 2-(1-((1-ethyl-5-methyl-1H-pyrazol-3-yl)methyl)-1H-tetrazol-5-yl)pyridine 8 which were found to be extremely potent compared to the positive controls. The SAR study proved the influence of the alkylation position of pyrazole derivative on the tetrazole ring, the nature of substituent on the tetrazolic carbon atom and the nature of the group at the nitrogen atom of the pyrazole ring on both α-amylase and glycation inhibition activity. Compounds 4 and 8 could be a good drug candidate to treat Type 2 diabetes.

Utilization of cyanopyridine in design and synthesis of first-in-class anticancer dual acting PIM-1 kinase/HDAC inhibitors

Herein, we report design and synthesis of twenty-one dual PIM-1/HDAC inhibitors utilizing 3-cyanopyridines as a novel cap moiety linked with aliphatic /aromatic linker bearing carboxylic acid 3a-g, hydroxamic acid 4a-g or 2-aminoanilide moieties 5a-g as zinc-binding group. Most of the target hybrids revealed promising growth inhibition according to one dose NCI protocol against 60 cancer cell lines. Meanwhile, hydroxamic acids 4b, 4d and 4e displayed strong and broad-spectrum activity against nine tumor subpanels tested (GI₅₀ 0.176-8.87 μM); 4d displayed strong antiproliferative activity with GI₅₀ ≤ 3 μM against different cancer cell lines (GI₅₀ range from 0.325 to 2.9 μM). Furthermore, 4a, 4d-4g and 5f manifested a high inhibitory activity against HDACs 1 and 6 isozymes; 4g, displayed potent HDAC 1 and 6 inhibitory activity (45.01 ± 2.1 and 19.78 ± 1.1 nM) more than the reference SAHA (51.54 ± 2.4 and 21.38 ± 1.2 nM, respectively), while 4f was more potent (30.09 ± 1.4 nM) than SAHA against HDAC 1 and less potent (30.29 ± 1.7 nM) than SAHA against HDAC 6. Hybrids 4b, 4d, 4e and 4f exhibited potent PIM-1 inhibitory activity; 4d showed comparable activity to quercetin (IC₅₀ of 343.87 ± 16.6 and 353.76 ± 17.1 nM, respectively); it exhibited pre G1 apoptosis and arrest cell cycle at G2/M phase. Moreover, it revealed good binding into pocket of HDACs 1,6 and PIM-1 kinase enzymes with good correlation with biological results. Moreover, 4b, 4d and 4e had reasonable drug-likeness properties according to Lipinski's rule. However, multitarget inhibitor of PIM-1/HDAC is a promising strategy in anticancer drug discovery; the most potent hybrids require further in vivo and clinical investigations.

New benzothieno[2,3-c]pyridines as non-steroidal CYP17 inhibitors: design, synthesis, anticancer screening, apoptosis induction, and in silico ADME profile studies

A series of [1]benzothieno[2,3-c]pyridines was synthesised. Most compounds were chosen by NCI-USA to evaluate their anticancer activity. Compounds 5a-c showed prominent growth inhibition against most cell lines. 5c was selected at five dose concentration levels. It exhibited potent broad-spectrum anticancer activity with a GI50 of 4 nM-37 µM. Cytotoxicity of 5a-c was further evaluated against prostate, renal, and breast cancer cell lines. 5c showed double and quadruple the activity of staurosporine and abiraterone, respectively, against the PC-3 cell line with IC50 2.08 µM. The possible mechanism of anti-prostate cancer was explored via measuring the CYP17 enzyme activity in mice prostate cancer models compared to abiraterone. The results revealed that 5c suppressed the CYP17 enzyme to 15.80 nM. Moreover, it was found to be equipotent to abiraterone in testosterone production. Cell cycle analysis and apoptosis were performed. Additionally, the ADME profile of compound 5c demonstrated both good oral bioavailability and metabolic stability.

New Multi-Targeted Antiproliferative Agents: Design and Synthesis of IC261-Based Oxindoles as Potential Tubulin, CK1 and EGFR Inhibitors

A series of 3-benzylideneindolin-2-one compounds was designed and synthesized based on combretastatin A-4 and compound IC261, a dual casein kinase (CK1)/tubulin polymerization inhibitor, taking into consideration the pharmacophore required for EGFR-tyrosine kinase inhibition. The new molecular entities provoked significant growth inhibition against PC-3, MCF-7 and COLO-205 at a 10 μM dose. Compounds 6-chloro-3-(2,4,6-trimethoxybenzylidene) indolin-2-one, 4b, and 5-methoxy-3-(2,4,6-trimethoxybenzylidene)indolin-2-one, 4e, showed potent activity against the colon cancer COLO-205 cell line with an IC50 value of 0.2 and 0.3 μM. A mechanistic study demonstrated 4b's efficacy in inhibiting microtubule assembly (IC50 = 1.66 ± 0.08 μM) with potential binding to the colchicine binding site (docking study). With an IC50 of 1.92 ± 0.09 μg/mL, 4b inhibited CK1 almost as well as IC261. Additionally, 4b and 4e were effective inhibitors of EGFR-TK with IC50s of 0.19 μg/mL and 0.40 μg/mL compared to Gifitinib (IC50 = 0.05 μg/mL). Apoptosis was induced in COLO-205 cells treated with 4b, with apoptotic markers dysregulated. Caspase 3 levels were elevated to more than three-fold, while Cytochrome C levels were doubled. The cell cycle was arrested in the pre-G1 phase with extensive cellular accumulation in the pre-G1 phase, confirming apoptosis induction. Levels of cell cycle regulating proteins BAX and Bcl-2 were also defective. The binding interaction patterns of these compounds at the colchicine binding site of tubulin and the Gifitinib binding site of EGFR were verified by molecular docking, which adequately matched the reported experimental result. Hence, 4b and 4e are considered promising potent multitarget agents against colon cancer that require optimization.

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.

Pharmacophore-linked pyrazolo[3,4-d]pyrimidines as EGFR-TK inhibitors: Synthesis, anticancer evaluation, pharmacokinetics, and in silico mechanistic studies

Targeting the epidermal growth factor receptors (EGFRs) with small inhibitor molecules has been validated as a potential therapeutic strategy in cancer therapy. Pyrazolo[3,4-d]pyrimidine is a versatile scaffold that has been exploited for developing potential anticancer agents. On the basis of fragment-based drug discovery, considering the essential pharmacophoric features of potent EGFR tyrosine kinase (TK) inhibitors, herein, we report the design and synthesis of new hybrid molecules of the pyrazolo[3,4-d]pyrimidine scaffold linked with diverse pharmacophoric fragments with reported anticancer potential. These fragments include hydrazone, indoline-2-one, phthalimide, thiourea, oxadiazole, pyrazole, and dihydropyrazole. The synthesized molecules were evaluated for their anticancer activity against the human breast cancer cell line, MCF-7. The obtained results revealed comparable antitumor activity with that of the reference drugs doxorubicin and toceranib. Docking studies were performed along with EGFR-TK and ADMET profiling studies. The results of the docking studies showed the ability of the designed compounds to interact with key residues of the EGFR-TK through a number of covalent and noncovalent interactions. The obtained activity of compound 25 (IC50  = 2.89 µM) suggested that it may serve as a lead for further optimization and drug development.

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.

Design, synthesis, and analysis of antiproliferative and apoptosis-inducing activities of nitrile derivatives containing a benzofuran scaffold: EGFR inhibition assay and molecular modelling study

New cyanobenzofurans derivatives 2-12 were synthesised, and their antiproliferative activity was examined compared to doxorubicin and Afatinib (IC₅₀ = 4.17-8.87 and 5.5-11.2 µM, respectively). Compounds 2 and 8 exhibited broad-spectrum activity against HePG2 (IC₅₀ = 16.08-23.67 µM), HCT-116 (IC₅₀ = 8.81-13.85 µM), and MCF-7 (IC₅₀ = 8.36-17.28 µM) cell lines. Compounds 2, 3, 8, 10, and 11 were tested as EGFR-TK inhibitors to demonstrate their possible anti-tumour mechanism compared to gefitinib (IC₅₀ = 0.90 µM). Compounds 2, 3, 10, and 11 displayed significant EGFR TK inhibitory activity with IC₅₀ of 0.81-1.12 µM. Compounds 3 and 11 induced apoptosis at the Pre-G phase and cell cycle arrest at the G2/M phase. They also increased the level of caspase-3 by 5.7- and 7.3-fold, respectively. The molecular docking analysis of compounds 2, 3, 10, and 11 indicated that they could bind to the active site of EGFR TK.

From triazolophthalazines to triazoloquinazolines: A bioisosterism-guided approach toward the identification of novel PCAF inhibitors with potential anticancer activity

Inhibition of PCAF bromodomain has been validated as a promising strategy for the treatment of cancer. In this study, we report the bioisosteric modification of the first reported potent PCAF bromodomain inhibitor, L-45 to its triazoloquinazoline bioisosteres. Accordingly, three new series of triazoloquinazoline derivatives were designed, synthesized, and assessed for their anticancer activity against a panel of four human cancer cells. Three derivatives demonstrated comparable cytotoxic activity with the reference drug doxorubicin. Among them, compound 22 showed the most potent activity with IC₅₀ values of 15.07, 9.86, 5.75, and 10.79 µM against Hep-G2, MCF-7, PC3, and HCT-116 respectively. Also, compound 24 exhibited remarkable cytotoxicity effects against the selected cancer cell lines with IC₅₀ values of 20.49, 12.56, 17.18, and 11.50 µM. Compounds 22 and 25 were the most potent PCAF inhibitors (IC₅₀, 2.88 and 3.19 μM, respectively) compared with bromosporine (IC₅₀, 2.10 μM). Follow up apoptosis induction and cell cycle analysis studies revealed that the bioisostere 22 could induce apoptotic cell death and arrest the cell cycle of PC3 at the G2/M phase. The in silico molecular docking studies were additionally performed to rationalize the PCAF inhibitory effects of new triazoloquinazoline bioisosteres.

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.

A green microwave method for synthesizing a more stable phthalazin-1-ol isomer as a good anticancer reagent using chemical plasma organic reactions

Conventional synthesis of the phthalazine has already allowed affording the phthalazin-1-one phthalazin-1-ol dynamic equilibrium that decreases the anticancer activity due to diminishing the concentration of the phthalazin-1-ol product. Nowadays, pure phthalazin-1-ol (5) can be gaining by using green microwave tools that increase the power of the phthalazine nucleus as an anticancer drug. A microscopic thermal kinetic parameter like activation energy and the pre-exponential factor of the chemical plasma organic reactions affording pure phthalazin-1-ol (5) is calculated by using DFT simulation is obtained. Then we fed these parameters into the exact Arrhenius model to evaluate the distribution of chemical equilibrium conditions for producing phthalazin-1-ol. The proposed novel models that matching between microscopic and macroscopic show that the thermal stability of the equivalent temperature of phthalazin-1-ol is more stable than phthalazinone-1-one (4) in case of using plasma organic effect (green microwave) at 485 K. The structures of the prepared compounds were explained by physical and spectral data like FT-IR, 1H-NMR. Moreover, the theoretical calculations of Gibbs entropy of the phase transfer confirmed the equilibrium state of phthalazin-1-ol with the experimental result is achieved. Briefly, we introduce a good study for obtaining more stable phthalazin-1-ol isomer by using a green microwave method which is considered as good anticancer reagents of phenolic group (OH) and p-propenyl-anisole precursor as anise oil analogous.

In vivo- and in silico-driven identification of novel synthetic quinoxalines as anticonvulsants and AMPA inhibitors

The lack of effective therapies for epileptic patients and the potentially harmful consequences of untreated seizure incidents have made epileptic disorders in humans a major health concern. Therefore, new and more potent anticonvulsant drugs are continually sought after, to combat epilepsy. On the basis of the pharmacophoric structural specifications of effective α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) antagonists with an efficient anticonvulsant activity, the present work reports the design and synthesis of two novel sets of quinoxaline derivatives. The anticonvulsant activity of the synthesized compounds was evaluated in vivo according to the pentylenetetrazol-induced seizure protocol, and the results were compared with those of perampanel as a reference drug. Among the synthesized compounds, 24, 28, 32, and 33 showed promising activities with ED₅₀ values of 37.50, 23.02, 29.16, and 23.86 mg/kg, respectively. Docking studies of these compounds suggested that AMPA binding could be the mechanism of action of these derivatives. Overall, the pharmacophore-based structural optimization, in vivo and in silico docking, and druglikeness studies indicated that the designed compounds could serve as promising candidates for the development of effective anticonvulsant agents with good pharmacokinetic profiles.

1,2,4-Triazolo[4,3-c]quinazolines: a bioisosterism-guided approach towards the development of novel PCAF inhibitors with potential anticancer activity

Targeting PCAF with small inhibitor molecules has emerged as a potential therapeutic strategy for the treatment of cancer.

The antimicrobial potential and pharmacokinetic profiles of novel quinoline-based scaffolds: synthesis and in silico mechanistic studies as dual DNA gyrase and DHFR inhibitors

The resistance of pathogenic microbes to currently available antimicrobial agents has been considered a global alarming concern.

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.

Synthetic and medicinal chemistry of phthalazines: Recent developments, opportunities and challenges

Fused diaza-heterocycles constitute the core structure of numerous bioactive natural products and effective therapeutic drugs. Among them, phthalazines have been recognized as remarkable structural leads in medicinal chemistry due to their wide application in pharmaceutical and agrochemical industries. Accessing such challenging pharmaceutical agents/drug candidates with high chemical complexity through synthetically efficient approaches remains an attractive goal in the contemporary medicinal chemistry and drug discovery arena. In this review, we focus on the recent developments in the synthetic routes towards the generation of phthalazine-based active pharmaceutical ingredients and their biological potential against various targets. The general reaction scope of these innovative and easily accessible strategies was emphasized focusing on the functional group tolerance, substrate and coupling partner compatibility/limitation, the choice of catalyst, and product diversification. These processes were also accompanied by the mechanistic insights where deemed appropriate to demonstrate meaningful information. Moreover, the rapid examination of the structure-activity relationship analyses around the phthalazine core enabled by the pharmacophore replacement/integration revealed the generation of robust, efficient, and more selective compounds with pronounced biological effects. A large variety of in silico methods and ADME profiling tools were also employed to provide a global appraisal of the pharmacokinetics profile of diaza-heterocycles. Thus, the discovery of new structural leads offers the promise of improving treatments for various tropical diseases such as tuberculosis, leishmaniasis, malaria, Chagas disease, among many others including various cancers, atherosclerosis, HIV, inflammatory, and cardiovascular diseases. We hope this review would serve as an informative collection of structurally diverse molecules enabling the generation of mature, high-quality, and innovative routes to support the drug discovery endeavors.

Synthesis, antimicrobial evaluation, DNA gyrase inhibition, and in silico pharmacokinetic studies of novel quinoline derivatives

Herein, we report the synthesis and in vitro antimicrobial evaluation of novel quinoline derivatives as DNA gyrase inhibitors. The preliminary antimicrobial activity was assessed against a panel of pathogenic microbes including Gram-positive bacteria (Streptococcus pneumoniae and Bacillus subtilis), Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), and fungal strains (Aspergillus fumigatus, Syncephalastrum racemosum, Geotrichum candidum, and Candida albicans). Compounds that revealed the best activity were subjected to further biological studies to determine their minimum inhibitory concentrations (MICs) against the selected pathogens as well as their in vitro activity against the E. coli DNA gyrase, to realize whether their antimicrobial action is mediated via inhibition of this enzyme. Four of the new derivatives (14, 17, 20, and 23) demonstrated a relatively potent antimicrobial activity with MIC values in the range of 0.66-5.29 μg/ml. Among them, compound 14 exhibited a particularly potent broad-spectrum antimicrobial activity against most of the tested strains of bacteria and fungi, with MIC values in the range of 0.66-3.98 μg/ml. A subsequent in vitro investigation against the bacterial DNA gyrase target enzyme revealed a significant potent inhibitory activity of quinoline derivative 14, which can be observed from its IC₅₀ value (3.39 μM). Also, a molecular docking study of the most active compounds was carried out to explore the binding affinity of the new ligands toward the active site of DNA gyrase enzyme as a proposed target of their activity. Furthermore, the ADMET profiles of the most highly effective derivatives were analyzed to evaluate their potentials to be developed as good drug candidates.

Novel 1,2,4-triazole derivatives: Design, synthesis, anticancer evaluation, molecular docking, and pharmacokinetic profiling studies

Three novel series of 1,2,4-triazole derivatives were designed and synthesized as potential adenosine A2B receptor antagonists. The design of the new compounds depended on a virtual screening of a previously constructed library of compounds targeting the human adenosine A2B protein. Spectroscopic techniques including ¹ H nuclear magnetic resonance (NMR) and ¹³ C NMR, and infrared and mass spectroscopy were used to confirm the structures of the synthesized compounds. The in vitro cytotoxicity evaluation was carried out against a human breast adenocarcinoma cell line (MDA-MB-231) using the MTT assay, and the obtained results were compared with doxorubicin as a reference anticancer agent. In addition, in silico studies to propose how the two most active compounds interact with the adenosine A2B receptor as a potential target were performed. Furthermore, a structure-activity relationship analysis was performed, and the pharmacokinetic profile to predict the oral bioavailability and other pharmacokinetic properties was also explained. Four of our designed derivatives showed promising cytotoxic effects against the selected cancer cell line. Compound 15 showed the highest activity with an IC₅₀ value of 3.48 µM. Also, compound 20 revealed an equipotent activity with the reference cytotoxic drug, with an IC₅₀ value of 5.95 µM. The observed IC₅₀ values were consistent with the obtained in silico docking scores. The newly designed compounds revealed promising pharmacokinetic profiles as compared with the reference marketed drug.

Unravelling the anticancer potency of 1,2,4-triazole-N-arylamide hybrids through inhibition of STAT3: synthesis and in silico mechanistic studies

The discovery of potent STAT3 inhibitors has gained noteworthy impetus in the last decade. In line with this trend, considering the proven biological importance of 1,2,4-triazoles, herein, we are reporting the design, synthesis, pharmacokinetic profiles, and in vitro anticancer activity of novel C3-linked 1,2,4-triazole-N-arylamide hybrids and their in silico proposed mechanism of action via inhibition of STAT3. The 1,2,4-triazole scaffold was selected as a privilege ring system that is embedded in core structures of a variety of anticancer drugs which are either in clinical use or still under clinical trials. The designed 1,2,4-triazole derivatives were synthesized by linking the triazole-thione moiety through amide hydrophilic linkers with diverse lipophilic fragments. In silico study to predict cytotoxicity of the new hybrids against different kinds of human cancer cell lines as well as the non-tumor cells was conducted. The multidrug-resistant human breast adenocarcinoma cells (MDA-MB-231) was found most susceptible to the cytotoxic effect of synthesized compounds and hence were selected to evaluate the in vitro anticancer activity. Four of the designed derivatives showed promising cytotoxicity effects against selected cancer cells, among which compound 12 showed the highest potency (IC₅₀ = 3.61 µM), followed by 21 which displayed IC₅₀ value of 3.93 µM. Also, compounds 14 and 23 revealed equipotent activity with the reference cytotoxic agent doxorubicin. To reinforce these observations, the obtained data of in vitro cytotoxicity have been validated in terms of ligand-protein interaction and new compounds were analyzed for ADMET properties to evaluate their potential to build up as good drug candidates. This study led us to identify two novel C3-linked 1,2,4-triazole-N-arylamide hybrids of interesting antiproliferative potentials as probable lead inhibitors of STAT3 with promising pharmacokinetic profiles.