Kinase Inhibitory Activity Research Articles

Design, synthesis, and biological evaluation of potent FAK-degrading PROTACs

FAK mediated tumour cell migration, invasion, survival, proliferation and regulation of tumour stem cells through its kinase-dependent enzymatic functions and kinase-independent scaffolding functions. At present, the development of FAK PROTACs has become one of the hotspots in current pharmaceutical research to solve above problems. Herein, we designed and synthesised a series of FAK-targeting PROTACs consisted of PF-562271 derivative 1 and Pomalidomide. All compounds showed significant in vitro FAK kinase inhibitory activity, the IC50 value of the optimised PROTAC A13 was 26.4 nM. Further, A13 exhibited optimal protein degradation (85% degradation at 10 nM). Meantime, compared with PF-562271, PROTAC A13 exhibited better antiproliferative activity and anti-invasion ability in A549 cells. More, A13 had excellent plasma stability with T 1/2 >194.8 min. There are various signs that PROTAC A13 could be useful as expand tool for studying functions of FAK in biological system and as potential therapeutic agents.

Identification of Novel Inhibitors Targeting SGK1 via Ensemble-Based Virtual Screening Method, Biological Evaluation and Molecular Dynamics Simulation.

Serum and glucocorticoid-regulated kinase 1 (SGK1), as a serine threonine protein kinase of the AGC family, regulates different enzymes, transcription factors, ion channels, transporters, and cell proliferation and apoptosis. Inhibition of SGK1 is considered as a valuable approach for the treatment of various metabolic diseases. In this investigation, virtual screening methods, including pharmacophore models, Bayesian classifiers, and molecular docking, were combined to discover novel inhibitors of SGK1 from the database with 29,158 compounds. Then, the screened compounds were subjected to ADME/T, PAINS and drug-likeness analysis. Finally, 28 compounds with potential inhibition activity against SGK1 were selected for biological evaluation. The kinase inhibition activity test revealed that among these 28 hits, hit15 exhibited the highest inhibition activity against SGK1, which gave 44.79% inhibition rate at the concentration of 10 µM. In order to further investigate the interaction mechanism of hit15 and SGK1 at simulated physiological conditions, a molecular dynamics simulation was performed. The molecular dynamics simulation demonstrated that hit15 could bind to the active site of SGK1 and form stable interactions with key residues, such as Tyr178, ILE179, and VAL112. The binding free energy of the SGK1-hit15 was −48.90 kJ mol−1. Therefore, the identified hit15 with novel scaffold may be a promising lead compound for development of new SGK1 inhibitors for various diseases treatment.

Synthesis and biological evaluation of 4-(4-aminophenyl)-6-methylisoxazolo[3,4-b] pyridin-3-amine covalent inhibitors as potential agents for the treatment of acute myeloid leukemia

Fms-like tyrosine kinase 3 (FLT3) mutation has been strongly associated with increased risk of relapse, and the irreversible covalent FLT3 inhibitors had the potential to overcome the drug-resistance. In this study, a series of simplified 4-(4-aminophenyl)-6-methylisoxazolo[3,4-b] pyridin-3-amine derivatives containing two types of Michael acceptors (vinyl sulfonamide, acrylamide) were conveniently synthesized to target FLT3 and its internal tandem duplications (ITD) mutants irreversibly. The kinase inhibitory activities showed that compound C14 displayed potent inhibition activities against FLT3 (IC50 = 256 nM) and FLT3-ITD by 73 % and 25.34 % respectively, at the concentration of 1 μM. The antitumor activities indicated that C14 had strong inhibitory activity against the human acute myeloid leukemia (AML) cell lines MOLM-13 (IC50 = 507 nM) harboring FLT3-ITD mutant, as well as MV4-11 (IC50 = 325 nM) bearing FLT3-ITD mutation. The biochemical analyses showed that these effects were related to the ability of C14 to inhibit FLT3 signal pathways, and C14 could induce apoptosis in MV4-11 cell as demonstrated by flow cytometry. Fortunately, C14 showed very weak potency against FLT3-independent human cervical cancer cell line HL-60 (IC50 > 10 μM), indicating that it might have no off-target toxic effects. In light of these data, compound C14 represents a novel covalent FLT3 kinase inhibitor for targeted therapy of AML.

Allosteric enhancement of the BCR-Abl1 kinase inhibition activity of nilotinib by cobinding of asciminib

Inhibitors that bind competitively to the ATP binding pocket in the kinase domain of the oncogenic fusion protein BCR–Abl1 are used successfully in targeted therapy of chronic myeloid leukemia (CML). Such inhibitors provided the first proof of concept that kinase inhibition can succeed in a clinical setting. However, emergence of drug resistance and dose-dependent toxicities limit the effectiveness of these drugs. Therefore, treatment with a combination of drugs without overlapping resistance mechanisms appears to be an appropriate strategy. In the present work, we explore the effectiveness of combination therapies of the recently developed allosteric inhibitor asciminib with the ATP-competitive inhibitors nilotinib and dasatinib in inhibiting the BCR–Abl1 kinase activity in CML cell lines. Through these experiments, we demonstrate that asciminib significantly enhances the inhibition activity of nilotinib, but not of dasatinib. Exploring molecular mechanisms for such allosteric enhancement via systematic computational investigation incorporating molecular dynamics, metadynamics simulations, and density functional theory calculations, we found two distinct contributions. First, binding of asciminib triggers conformational changes in the inactive state of the protein, thereby making the activation process less favorable by ∼4 kcal/mol. Second, the binding of asciminib decreases the binding free energies of nilotinib by ∼3 and ∼7 kcal/mol for the wildtype and T315I-mutated protein, respectively, suggesting the possibility of reducing nilotinib dosage and lowering risk of developing resistance in the treatment of CML.

Molecular Docking and In Vitro Anticancer Screening of Synthesized Arylthiazole linked 2H-indol-2-one Derivatives as VEGFR-2 Kinase Inhibitors.

Indoline-2,3-dione comprises a leading course group of heterocycles endowed with appealing biological actions, including anticancer activity. There are significant justifications for exploring the anticancer activity of Schiff base derivatives of isatin as a vast number of reports have documented remarkable antiproliferative action of isatin nucleus against various cancer cell lines. A series of arylthiazole linked 2H-indol-2-one derivatives (5a-t) was designed and synthesized as potential VEGFR-2 kinase inhibitors keeping the essential pharmacophoric features of standard drugs, like sunitinib, sorafenib, nintedanib, etc. They were evaluated for their in vitro anticancer activity. The aim of this study was to investigate and assess the anticancer potential of isatin-containing compounds along with their kinase inhibition activity. The title compounds were synthesized by reacting substituted isatins with para-substituted arylthiazoles using appropriate reaction conditions. Selected synthesized derivatives went under preliminary screening against a panel of 60 cancer cell lines at NCI, the USA, for single-dose and five dose assays. Molecular docking was performed to explore the binding and interactions with the active sites of the VEGFR-2 receptor (PDB Id: 3VHE). Derivatives 5a, 5b, 5c, 5d, 5g, 5h, and 5m were assessed for in vitro inhibition potency against Human VEGFR-2 using ELISA (Enzyme- Linked Immunosorbent Assay) kit. All the target compounds were determined against human colon cancer cell line SW480 (colorectal adenocarcinoma cells). Cellular apoptosis/necrosis was determined by flow cytometry using annexin V-FITC. DNA content of the cells was analyzed by flow cytometry and the cycle distribution was quantified. Compounds 5a and 5g exhibited noteworthy inhibition during a five-dose assay against a panel of 60 cell lines with MID GI50 values of 1.69 and 1.54 μM, respectively. Also, both the lead compounds 5a and 5g demonstrated promising VEGFR-2 inhibitory activity with IC50 values of 5.43±0.95 and 9.63±1.32 μM, respectively. The aforesaid potent compounds were found effective against SW480 (colorectal adenocarcinoma cells) with IC50 values of 31.44 μM and 106.91 μM, respectively. Compound 5a was found to arrest the cell cycle at the G2/M phase, increasing apoptotic cell death. The docking study also supported VEGFR-2 inhibitory activity as both compounds 5a and 5g displayed promising binding and interactions with the active sites of VEGFR-2 receptor (PDB: 3VHE) with docking scores - 9.355 and -7.758, respectively. All the compounds obeyed Lipinski's rule of five. Indoline-2,3-dione and thiazole have huge potential to be considered a steer combination approach for developing promising kinase inhibitors as cancer therapeutics.

Discovery of novel 4-arylamino-quinazoline derivatives as EGFRL858R/T790M inhibitors with the potential to inhibit the non-small cell lung cancers

Three series of quinazoline derivatives (7a-j, 8a-o, 9a-l) were designed and synthesized as EGFRL858R/T790M inhibitors. Series 7a-j and 8a-o are urea and thiourea derivatives while category 9a-l contain the Michael receptor active warhead. Most of the compounds exhibited excellent anti-proliferative activity in vitro against several cancer cell lines, including non-small cell lung cancer (NSCLC) cell lines A549 and H1975, among which 14 compounds had strong antiproliferative activity against A549 and H1975 cancer cells. What’s more, they also showed moderate to excellent kinase inhibitory activity against EGFRWT and EGFRL858R/T790M. 8o exhibited the best kinase inhibitory activity with IC50 values of 0.8, 2.7 nM against EGFRWT and EGFRL858R/T790M, respectively. Moreover, AO single staining and Annexin V-FITC/PI staining results also indicated that both 8o and 9b significantly induced apoptosis in A549 cells. 8o arrested the cell cycle at S phase and 9b arrested the cell cycle at G1 phase.

Structural dynamics and kinase inhibitory activity of three generations of tyrosine kinase inhibitors against wild-type, L858R/T790M, and L858R/T790M/C797S forms of EGFR

Mutations in the tyrosine kinase domain of epidermal growth factor receptor (EGFR), including L858R/T790M double and L858R/T790M/C797S triple mutations, are major causes of acquired resistance towards EGFR targeted drugs. In this work, a combination of comprehensive molecular modeling and in vitro kinase inhibition assay was used to unravel the mutational effects of EGFR on the susceptibility of three generations of EGFR tyrosine kinase inhibitors (erlotinib, gefitinib, afatinib, dacomitinib, and osimertinib) in comparison with the wild-type EGFR. The binding affinity of all studied inhibitors towards the double and triple EGFR mutations was in good agreement with the experimental data, ranked in the order of osimertinib > afatinib > dacomitinib > erlotinib > gefitinib. Three hot-spot residues at the hinge region (M790, M793, and C797) were involved in the binding of osimertinib and afatinib, enhancing their inhibitory activity towards mutated EGFRs. Both double and triple EGFR mutations causing erlotinib and gefitinib resistance are mainly caused by the low number of H-bond occupations, the low number of surrounding atoms, and the high number of water molecules accessible to the enzyme active site. According to principal component analysis, the molecular complexation of osimertinib against the two mutated EGFRs was in a closed conformation, whereas that against wild-type EGFR was in an open conformation, resulting in drug resistance. This work paves the way for further design of the novel EGFR inhibitors to overcome drug resistance mechanisms.

Identification of (S)-1-(2-(2,4-difluorophenyl)-4-oxothiazolidin-3-yl)-3-(4-((7-(3-(4-ethylpiperazin-1-yl)propoxy)-6-methoxyquinolin-4-yl)oxy)-3,5-difluorophenyl)urea as a potential anti-colorectal cancer agent

In our previous study, 1-(2-(2,6-difluorophenyl)-4-oxothiazolidin-3-yl)-3-(4-((7-(3-(4-ethylpiperazin-1-yl)propoxy)-6-methoxyquinolin-4-yl)oxy)-3,5-difluorophenyl)urea (1) was obtained as a potent tyrosine kinase inhibitor. Further structural optimization was performed in this investigation, and a series of novel quinoline derivates were designed, synthesized and evaluated for their biological activity. Among them, compound 8m possessed nanomolar c-Met and Ron inhibitory activity, with IC50 values of 4.32 nM and 2.39 nM, respectively. Kinase profile study demonstrated that it could also inhibit ABL, PDGFRβ, AXL, RET, and FLT3 with submicromolar potency. It also exhibited moderate to excellent cytotoxic activity against different types of human cancer cell lines, especially against COLO 205 cells (IC50 = 0.035 μM) which was remarkably superior to that of Cabozantinib (IC50 = 6.6 μM) and Fruquintinib (IC50 > 10.0 μM). Compared to ( ± )-8m, isomer (S)-8m and (R)-8m showed similar kinase inhibitory activity against c-Met/RON and in vitro anticancer activity against COLO 205 cells. Differently, compound (S)-8m showed an over 238-fold selectivity toward COLO 205 (IC50 = 0.042 μM) cells to FHC cells (IC50 > 10.0 μM), which indicated its low cytotoxicity against human normal tissue cells. Flow cytometry study demonstrated that compound (S)-8m could significantly induce apoptosis in COLO 205 cells in a dose-dependent manner. Cell cycle arrest assays showed that compound (S)-8m could not arrest the cell-cycle progression due to the massive dead cells.

Identification of a Unique Cytotoxic Thieno[2,3-c]Pyrazole Derivative with Potent and Selective Anticancer Effects In Vitro.

Simple SummaryDespite their documented antitumor effects, thienopyrazole-based compounds remain an underexplored class of molecules. In this study, a screening of 2000 novel molecules revealed a unique thienopyrazole derivative, Tpz-1, that elicited potent and selective programmed cell death in human blood, breast, colon, and cervical cancer cell lines when compared to non-cancerous human fibroblast (Hs27) cells. Furthermore, in HL-60 leukemia cells, Tpz-1 interfered with components of signaling pathways and the cytoskeleton that are important to cell shape, internal organization, growth, and division. These findings encourage the continued investigation and development of Tpz-1 and other thienopyrazole derivatives to target and treat cancers.In recent years, the thienopyrazole moiety has emerged as a pharmacologically active scaffold with antitumoral and kinase inhibitory activity. In this study, high-throughput screening of 2000 small molecules obtained from the ChemBridge DIVERset library revealed a unique thieno[2,3-c]pyrazole derivative (Tpz-1) with potent and selective cytotoxic effects on cancer cells. Compound Tpz-1 consistently induced cell death at low micromolar concentrations (0.19 μM to 2.99 μM) against a panel of 17 human cancer cell lines after 24 h, 48 h, or 72 h of exposure. Furthermore, an in vitro investigation of Tpz-1’s mechanism of action revealed that Tpz-1 interfered with cell cycle progression, reduced phosphorylation of p38, CREB, Akt, and STAT3 kinases, induced hyperphosphorylation of Fgr, Hck, and ERK 1/2 kinases, and disrupted microtubules and mitotic spindle formation. These findings support the continued exploration of Tpz-1 and other thieno[2,3-c]pyrazole-based compounds as potential small-molecule anticancer agents.

In Vitro Anticancer Activity Screening of Novel Fused Thiophene Derivatives as VEGFR-2/AKT Dual Inhibitors and Apoptosis Inducers.

Protein kinases are seen as promising targets in controlling cell proliferation and survival in treating cancer where fused thiophene synthon was utilized in many kinase inhibitors approved by the FDA. Accordingly, this work focused on adopting fused thienopyrrole and pyrrolothienopyrimidine scaffolds in preparing new inhibitors, which were evaluated as antiproliferative agents in the HepG2 and PC-3 cell lines. The compounds 3b (IC50 = 3.105 and 2.15 μM) and 4c (IC50 = 3.023 and 3.12 μM) were the most promising candidates on both cells with good selective toxicity-sparing normal cells. A further mechanistic evaluation revealed promising kinase inhibitory activity, where 4c inhibited VEGFR-2 and AKT at IC50 = 0.075 and 4.60 μM, respectively, while 3b showed IC50 = 0.126 and 6.96 μM, respectively. Moreover, they resulted in S phase cell cycle arrest with subsequent caspase-3-induced apoptosis. Lastly, docking studies evaluated the binding patterns of these active derivatives and demonstrated a similar fitting pattern to the reference ligands inside the active sites of both VEGFR-2 and AKT (allosteric pocket) crystal structures. To conclude, these thiophene derivatives represent promising antiproliferative leads inhibiting both VEGFR-2 and AKT and inducing apoptosis in liver cell carcinoma.

Narazaciclib’s kinase inhibitory activity is differentiated from approved CDK4/6 inhibitors in preclinical models.

e15096 Background: Despite clinical benefit of CDK4/6 inhibitors in HR+Her2-mBC, patients progress. Neutropenia and diarrhea are safety concerns. Narazaciclib (ON 123300) is a multi-targeted kinase inhibitor of CDK4/6, ARK5 (NUAK1), CSF1R, and c-Kit at low nM concentrations designed to enhance efficacy and safety. Narazaciclib is in Ph I trials; NCT04739293 and CXHL1900340; in different regimens. Treatment of tumor cell lines with narazaciclib induces G1; G2 arrest and apoptosis. Mouse models suggest narazaciclib causes less neutropenia than palbociclib (palbo). Since signaling pathways are affected, we explored the activity of narazaciclib in direct comparisons with abemaciclib (abe), palbo and ribociclib (ribo) using in vitro and cell based assays. Methods: Comparison of narazaciclib’s in vitro IC50 profile to abe, palbo and ribo was studied against a panel of 370 kinases (HotSpot). Kd values were determined by KINOMEscan. Intracellular IC50 kinase values were determined by NanoBret technology. Protein specific binding of narazaciclib and palbo was investigated by Cellular Thermal Shift Assay (CETSA). To investigate narazaciclib’s effect on signaling pathways, integrative Inferred Kinase Activity (INKA) analysis was performed. Results: Narazaciclib and abe were found to be the most promiscuous in vitro kinase inhibitors and ribo the most specific. Abe and narazaciclib had similar profiles against the CDK family members. Kd values of CDK4/cyclinD1 binding show similar trends; abe (0.08 nM), narazaciclib (0.18 nM), palbo (0.75 nM) and ribo (1.3 nM). Narazaciclib and abe displayed nM activity against CDK2/cyclinA. The IC50 values against GSK3β, whose inhibition putatively causes diarrhea, was 374 nM for narazaciclib and 13 nM for abe. Although narazaciclib displayed nM IC50 values in the in vitro assays against many CDKs, narazaciclib was very specific in cellular kinase assays with highest activity against CDK4/6, CSF1R and NUAK1. CETSA-MS revealed more potential targets engaged by narazaciclib compared to palbo in both lysates and intact cells such as CHEK1, AAK1, BMP2K, GSK3α and GSK3β, but did not identify binding to NUAK1 or CSF1R. INKA analysis demonstrated that narazaciclib induced unique deregulated phosphorylation compared to palbo, including BUB1 (highly expressed in TNBC), NUAK1, CAMK2D, CDK16 and ULK1. Inhibition of autophagy, both at early and late stages, may sensitize cancer cells to narazaciclib and induce irreversible cell proliferation inhibition, providing a novel therapeutic approach. Conclusions: These studies identify important differences generated from assay models studying kinase inhibition, binding and pathway engagement and will guide future studies with narazaciclib targeting specific kinase driven tumors with the potential for improved safety. These preclinical data await confirmation from current and future clinical trials.

Design, synthesis and biological evaluation of novel triazoloquinazolinone and imidazoquinazolinone derivatives as allosteric inhibitors of SHP2 phosphatase

ABSTRCT A series of novel triazoloquinolinone and imidazoquinazolinone derivatives were designed and synthesised, and their biological activities against SHP2 protein and melanoma A357 cell line were evaluated in vitro. The results show that some target compounds have moderate to excellent inhibitory activity on SHP2 protein and melanoma A357 cell line. Structure-activity relationships (SARs) showed that both imidazoquinazolinone and triazoloquinazolinone derivatives have good SHP2 protein kinase and melanoma cell line A357 inhibitory activity. The results of molecular docking also showed that the cores of imidazoquinazolinone and triazoloquinazolinone have a certain affinity for SHP2 protein at the same time. Compared with SHP244, the target compounds have quite good liver microsomal stability and has more drug potential. The most promising compound B1 has a strong inhibitory effect on the melanoma cell line A357 at 100 µM (76.15% inhibition).

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).

In Vitro Anti-Proliferative, and Kinase Inhibitory Activity of Phenanthroindolizidine Alkaloids Isolated from Tylophora indica.

The phenanthroindolizidine alkaloid (-)-tylophorine has been reported for its significant anticancer activity working through different biomechanistic pathways. The current study aimed to evaluate the anticancer activity of phenanthroindolizidine alkaloids isolated from Tylophora indica. Six phenanthroindolizidine alkaloid (compounds 1–6) in addition to septicine (7), chlorogenic acid (8), and chlorogenic acid methyl ester (9) were isolated from Tylophora indica using different chromatographic techniques including vacuum liquid chromatography (VLC) and preparative high performance liquid chromatography (HPLC). The isolated compounds structures’ were determined using various spectro-analytical techniques, i.e., 1H-NMR, 13C-NMR, and mass spectrometry. The isolates’ structural stereochemistry and structural geometries were determined with the help of chiroptical techniques together with comparisons with the available standard samples. The in vitro anti-proliferative activity on three different cell lines, MCF-7, HepG2, and HCT-116 were evaluated. Among all the isolated compounds, tylophorinidine (5) was the most active cytotoxic agent with the lowest IC50 values at 6.45, 4.77, and 20.08 μM against MCF-7, HepG2, and HCT-116 cell lines, respectively. The bioactivities were also validated by the in vitro kinase receptors inhibition assay. Compound (5) also exhibited the highest activity with lowest IC50 values (0.6 and 1.3 μM against the Aurora-A and Aurora-B enzymes, respectively), as compared with all the isolated alkaloidal products. The structure activity relationship on the molecular properties, molecular attributes, and bioactivity levels were analyzed, interrelated, and the molecular docking studies on two different receptors, Aurora-A and Aurora-B, were determined, which provided the confirmations of the bioactivity with receptor-ligand geometric disposition, energy requirements, lipophilicity, and detailed the binding pharmacophore involvements responsible for bioactivity elicitations.

Synthesis of 4-styrylpyrazoles and Evaluation of their Inhibitory Effects on Cyclin-dependent Kinases.

Cycle-regulating and transcriptional cyclin-dependent kinases (CDKs) are attractive targets in cancer drug development. Several CDK inhibitors have already been obtained or are close to regulatory approval for clinical applications. Phenylazopyrazole CAN508 has been described as the first selective CDK9 inhibitor with an IC50 of 350 nM. Since the azo-moiety is not a suitable functionality for drugs due to pharmacological reasons, the preparation of carbo-analogues of CAN508 with similar biological activities is desirable. The present work is focused on the synthesis of carbo-analogues similar to CAN508 and their CDK inhibition activity. Herein, the synthesis of 21 novel carbo analogues of CAN508 and their intermediates is reported. Subsequently, target compounds 8a - 8u were evaluated for protein kinase inhibition (CDK2/cyclin E, CDK4/cyclin D, CDK9/cyclin T) and antiproliferative activities in cell lines (K562, MCF-7, MV4-11). Moreover, the binding mode of derivative 8s in the active site of CDK9 was modelled. Compounds 8a - 8u were obtained from key intermediate 7, which was prepared by linear synthesis involving Vilsmeier-Haack, Knoevenagel, Hunsdiecker, and Suzuki-Miyaura reactions. Styrylpyrazoles 8t and 8u were the most potent CDK9 inhibitors with IC50 values of approximately 1 μM. Molecular modelling suggested binding in the active site of CDK9. The flow cytometric analysis of MV4-11 cells treated with the most active styrylpyrazoles showed a significant G1-arrest. The prepared styrylpyrazoles showed inhibition activity towards CDKs and can provide a novel chemotype of kinase inhibitors.

Explorations of novel pyridine-pyrimidine hybrid phosphonate derivatives as aurora kinase inhibitors

For developing novel therapeutic agents with good anticancer activities, a series of novel pyridine-pyrimidine hybrid phosphonate derivatives4(a–q) were synthesized by the Kabachnik-Fields method using CAN as catalyst. The compound 4o exhibited the most potent anticancer activity with an IC50 value of 13.62 μM, 17.49 μM, 5.81 μM, 1.59 μM and 2.11 μM against selected cancer cell lines A549, Hep-G2, HeLa, MCF-7, and HL-60, respectively. Compound 4o displayed seven times more selectivity towards Hep-G2 cancer cell lines compared to the human normal hepatocyte cell line LO2 (IC50 value 95.33 μM). Structure-Activity Relationship (SAR) studies were conducted on the variation in the aromatic ring (five-membered heterocyclic ring, six-membered heterocyclic ring) and the variation of substituents on the phenyl ring (electron donating groups, electron withdrawing groups). Furthermore, the mechanism of anticancer activity was clarified by further explorations in bioactivity by using in vitro aurora kinase inhibitory activity and molecular docking studies. The results showed that the compound 4o at IC50concentrationdemonstrated distinctive morphological changes such as cell detachment, cell wall deformation, cell shrinkage and reduced number of viable cells in cancer cell lines. Compound 4o induced early apoptosis and late apoptosis of 27.7% and 6.1% respectively.

In Silico Screening for Novel Tyrosine Kinase Inhibitors with Oxindole Scaffold as Anti-Cancer Agents: Design, QSAR Analysis, Molecular Docking and ADMET Studies

Recently, anti-cancer targeting drugs are directed against specific molecules and signaling pathways. These targeting agents have reasonable specificity, efficacy and less side effects. Tyrosine kinases, which play an essential role in growth factor signaling regulation, are significant targets in this type of therapy. Synthesized numerous tyrosine-kinase inhibitors (TKIs), such as substituted indolin-2-ones, are effective as anti-tumor and anti-leukemia agents. In this study, a series of novel substituted indolin-2-ones were studied as kinase inhibitor analogs through quantitative structure–activity relationship (QSAR) analysis. Two chemometrics methods, such as multiple linear regression (MLR) and partial least squares combined with genetic algorithm for variable selection (GA-PLS), were employed to establish relationships between structural characteristics and kinase inhibitory activity of used oxindole analogs. The GA-PLS was developed as the best predictor and validated QSAR model. The data set compounds were also studied by molecular docking to investigate their binding mechanism in the active site of tyrosine kinase enzyme. According to the information obtained from QSAR models and molecular docking analysis, 40 new potent lead compounds with novel structural features were introduced. Molecular docking, drug-likeness rules, ADMET analysis, bioavailability, toxicity prediction and target identification were carried out on the newly designed oxindoles to elucidate fundamental structural properties that affect their inhibitory activity.

Synthesis and biological evaluation of Haspin inhibitors: Kinase inhibitory potency and cellular activity

Haspin (haploid germ cell-specific nuclear protein kinase) offers a potential target for the development of new anticancer drugs. Thus, the identification of new inhibitors targeting this protein kinase is of high interest. However, Haspin inhibitors developed to date show a poor selectivity profile over other protein kinases of the human kinome. Here, we identified a new pyridoquinazoline based inhibitor (4), with excellent inhibitory activity and selectivity for Haspin (IC50 of 50 nM). We describe the structure-activity relationship study including the evaluation of this inhibitor on a large panel of 486 kinases as well as on immortalized or cancer cell lines. In addition, we determined the binding mode of analog 2a in complex with Haspin using X-ray crystallography.

Design, Synthesis, and Biological Evaluation of [1,2,4]triazolo[4,3-a] Pyrazine Derivatives as Novel Dual c-Met/VEGFR-2 Inhibitors.

In this study, we designed and synthesized a series of novel [1,2,4]triazolo [4,3-a]pyrazine derivatives, and evaluated them for their inhibitory activities toward c-Met/VEGFR-2 kinases and antiproliferative activities against tested three cell lines in vitro. Most of the compounds showed satisfactory activity compared with lead compound foretinib. Among them, the most promising compound 17l exhibited excellent antiproliferative activities against A549, MCF-7, and Hela cancer cell lines with IC50 values of 0.98 ± 0.08, 1.05 ± 0.17, and 1.28 ± 0.25 µM, respectively, as well as excellent kinase inhibitory activities (c-Met IC50 = 26.00 nM and VEGFR-2 IC50 = 2.6 µM). Moreover, compound 17l inhibited the growth of A549 cells in G0/G1 phase in a dose-dependent manner, and induced the late apoptosis of A549 cells. Its intervention on intracellular c-Met signaling of A549 was verified by the result of Western blot. Fluorescence quantitative PCR showed that compound 17l inhibited the growth of A549 cells by inhibiting the expression of c-Met and VEGFR-2, and its hemolytic toxicity was low. Molecular docking and molecular dynamics simulation indicated that compound 17l could bind to c-Met and VEGFR-2 protein, which was similar to that of foretinib.

O-methylated flavonol as a multi-kinase inhibitor of leukemogenic kinases exhibits a potential treatment for acute myeloid leukemia

BackgroundAcute myeloid leukemia (AML) is a heterogeneous disease with poor overall survival characterized by various genetic changes. The continuous activation of oncogenic pathways leads to the development of drug resistance and limits current therapeutic efficacy. Therefore, a multi-targeting inhibitor may overcome drug resistance observed in AML treatment. Recently, groups of flavonoids, such as flavones and flavonols, have been shown to inhibit a variety of kinase activities, which provides potential opportunities for further anticancer applications. PurposeIn this study, we evaluated the anticancer effects of flavonoid compounds collected from our in-house library and investigated their potential anticancer mechanisms by targeting multiple kinases for inhibition in AML cells. MethodsThe cytotoxic effect of the compounds was detected by cell viability assays. The kinase inhibitory activity of the selected compound was detected by kinase-based and cell-based assays. The binding conformation and interactions were investigated by molecular docking analysis. Flow cytometry was used to evaluate the cell cycle distribution and cell apoptosis. The protein and gene expression were estimated by western blotting and qPCR, respectively. ResultsIn this study, an O-methylated flavonol (compound 11) was found to possess remarkable cytotoxic activity against AML cells compared to treatment in other cancer cell lines. The compound was demonstrated to act against multiple kinases, which play critical roles in survival signaling in AML, including FLT3, MNK2, RSK, DYRK2 and JAK2 with IC50 values of 1 - 2 μM. Compared to our previous flavonoid compounds, which only showed inhibitions against MNKs or FLT3, compound 11 exhibited multiple kinase inhibitory abilities. Moreover, compound 11 showed effectiveness in inhibiting internal tandem duplications of FLT3 (FLT3-ITDs), which accounts for 25% of AML cases. The interactions between compound 11 and targeted kinases were investigated by molecular docking analysis. Mechanically, compound 11 caused dose-dependent accumulation of leukemic cells at the G0/G1 phase and followed by the cells undergoing apoptosis. ConclusionO-methylated flavonol, compound 11, can target multiple kinases, which may provide potential opportunities for the development of novel therapeutics for drug-resistant AMLs. This work provides a good starting point for further compound optimization.