Discovery of potential RSK1 inhibitors for cancer therapy using virtual screening, molecular docking, molecular dynamics simulation, and MM/GBSA calculations.

The p90 ribosomal protein S6 Kinase (RSK) family belongs to Ser/Thr protein kinases that includes four isoform RSK1-4 in mammals. The ribosomal protein S6 Kinase 1 (RSK1) is also known as ribosomal protein S6 kinase alpha-1 (RPS6KA1) is a special protein due to their two catalytic regions that is associated with abundantly various cancers and it is proposed as a drug target. Several RSK1 isoform inhibitors have been reported but none of them are used in clinical studies. Thus, we aimed to perform ligand pharmacophore mapping with the known inhibitor and structure-based virtual screening studies to determine potential candidates against RSK1-terminal kinase domains CTKD and NTKD. The studied compounds from the databases (ApexBio, ChEMBL, ChemDiv). The molecular docking study was performed with the resulted candidates by using CDOCKER and Glide/SP methods. The four candidates with the highest docking scores were used for further 100-ns molecular dynamics (MD) simulations and Molecular Mechanics Generalised Born and Surface Area (MM/GBSA) calculations. The root mean square deviation (RMSD) for protein complexes were found between 2 Å and 4 Å. Solvent accessible surface area (SASA), radius of gyration (Rg), and polar surface area (PSA) values were calculated for compounds. The binding free energies were calculated between -72.22 kcal/mol and -82.44 kcal/mol. The interaction diagrams showed that hydrogen bond, alkyl, and π-alkyl interactions were observed with specific residues such as Leu144, Lys94, Asp142 for RSK1-NTKD, and Cys532, Cys556, Lys447, Asn540 for RSK1-CTKD. The identified compounds may be potential inhibitor candidates of RSK1 following the preclinical studies.Communicated by Ramaswamy H. Sarma.

Synthesis, anticancer activity and molecular modeling study of novel substituted triazole linked tetrafluoronaphthalene hybrid derivatives.

To create some novel anticancer molecules, a library of novel series of various triazoles linked to the hydroxyl group of 5,6,7,8-tetrafluoronaphthalen-1-ol (3) was designed and synthesized via CuAAC reaction 'Click Chemistry' of tetrafluoronaphthalene based terminal alkyne with substituted organic azides. The structural characterizations of the targeted Click products 9-18 were confirmed by FTIR, 1H NMR, 19F NMR, 13C NMR and HRMS spectroscopy. Synthesized compounds were tested in two triple negative breast cancer (TNBC) cell lines to understand their anticancer potentials. According to our findings, compounds 14 and 13 showed high cytotoxicity in BT549 cells at 20 µM and 30 µM, respectively. Moreover, these compounds blocked the migration of BT549 cells. In the MDA-MB-231 cell line, compound 18 exhibited high cytotoxicity and can block cell migration for 24 h. Molecular docking study with synthesized novel compounds was performed by Glide/SP method against SphK1 drug target. Furthermore, molecular dynamics (MD) simulation was carried out for the compounds 12-14 and 18. The compounds 13 and 14 may be potential inhibitor candidates in place of a reference inhibitor. A pharmacophore model was generated with the most potent compound 14, and the approved drugs were screened using the modules of Discovery Studio to find similar drugs. Consequently, this comprehensive study encompassing design, synthesis, in vitro and in silico analyses were correlated with the structure-activity relationship between compounds. The findings have the potential to unveil promising drug candidates for future studies.Communicated by Ramaswamy H. Sarma.

Novel etodolac derivatives as eukaryotic elongation factor 2 kinase (eEF2K) inhibitors for targeted cancer therapy.

Eukaryotic elongation factor 2 kinase (eEF2K) has been shown to be an important molecular driver of tumorigenesis and validated as a potential novel molecular target in various solid cancers including triple negative breast cancer (TNBC). Therefore, there has been significant interest in identifying novel inhibitors of eEF2K for the development of targeted therapeutics and clinical translation. Herein, we investigated the effects of indole ring containing derivatives of etodolac, a nonsteroidal anti-inflammatory (NSAID) drug, as potential eEF2K inhibitors and we designed and synthesized seven novel compounds with a pyrano[3,4-b] indole core structure. We evaluated the eEF2K inhibitory activity of seven of these novel compounds using in silico molecular modeling and in vitro studies in TNBC cell lines. We identified two novel compounds (EC1 and EC7) with significant in vitro activity in inhibiting eEF2K in TNBC cells. In conclusion, our studies indicate that pyrano[3,4-b] indole scaffold containing compounds demonstrate marked eEF2K inhibitory activity and they may be used as eEF2K inhibitors for the development of eEF2K-targeted therapeutics.

Correction to "Target-Driven Design of a Coumarinyl Chalcone Scaffold Based Novel EF2 Kinase Inhibitor Suppresses Breast Cancer Growth In Vivo".

[This corrects the article DOI: 10.1021/acsptsci.1c00030.].

Target-Driven Design of a Coumarinyl Chalcone Scaffold Based Novel EF2 Kinase Inhibitor Suppresses Breast Cancer Growth In Vivo.

Eukaryotic elongation factor 2 kinase (eEF-2K) is an unusual alpha kinase involved in protein synthesis through phosphorylation of elongation factor 2 (EF2). eEF-2K is highly overexpressed in breast cancer, and its activity is associated with significantly shortened patient survival and proven to be a potential molecular target in breast cancer. The crystal structure of eEF-2K remains unknown, and there is no potent, safe, and effective inhibitor available for clinical applications. We designed and synthesized several generations of potential inhibitors. The effect of the inhibitors at the binding pocket of eEF-2K was analyzed after developing a 3D target model by using a domain of another α-kinase called myosin heavy-chain kinase A (MHCKA) that closely resembles eEF-2K. In silico studies showed that compounds with a coumarin-chalcone core have high predicted binding affinities for eEF-2K. Using in vitro studies in highly aggressive and invasive (MDA-MB-436, MDA-MB-231, and BT20) and noninvazive (MCF-7) breast cancer cells, we identified a lead compound that was highly effective in inhibiting eEF-2K activity at submicromolar concentrations and at inhibiting cell proliferation by induction of apoptosis with no toxicity in normal breast epithelial cells. In vivo systemic administration of the lead compound encapsulated in single lipid-based liposomal nanoparticles twice a week significantly suppressed growth of MDA-MB-231 tumors in orthotopic breast cancer models in nude mice with no observed toxicity. In conclusion, our study provides a highly potent and in vivo effective novel small-molecule eEF-2K inhibitor that may be used as a molecularly targeted therapy breast cancer or other eEF-2K-dependent tumors.

Delivery of Small Molecule EF2 Kinase Inhibitor for Breast and Pancreatic Cancer Cells Using Hyaluronic Acid Based Nanogels.

PURPOSE: To evalauted natural polymeric biomaterials including hyaluronic acid (HA) and its copolymeric form HA:Suc nanoparticles (NPs) as drug carrier systems for delivery of hydrophobic small molecule kinase EF2-kinase inhibitor in breast and pancreatic cancer cells. METHODS: In vitro cellular uptake studies of Rhodamine 6G labaled HA:Suc nanoparticles were evaluated by using flow cytometry analysis and fluorescent microscopy in breast (MDA-MB-231 and MDA-MB-436) and pancreatic cancer cells (PANC-1 and MiaPaca-2). Besides, in vitro release study of compound A (an EF2-kinase inhibitor) as a model hydrophobic drug was performed in the cancer cells. RESULTS: These biological evaluation studies indicated that HA and HA:Suc NPs provided a highly effective delivery of compound A were into breast and pancreatic cancer cells, leading to significant inhibition of cell proliferation and colony formation of breast and pancreatic cancer cells. CONCLUSION: HA-sucrose NPs incorporating an EF2-Kinase inhibitor demonstrate significant biologic activity in breast and pancreatic cancer cells. This is the first study that shows natural polymeric drug carriers succesfully deliver a hydrofobic cancer drug into cancer cells. Graphical Abstract Nanoparticles based on HA:Suc are effective in delivering hydrofobic cancer drugs in breast and pancreatic cancers.

Design, Synthesis, and Molecular Modeling Studies of Novel Coumarin Carboxamide Derivatives as eEF-2K Inhibitors.

Eukaryotic elongation factor-2 kinase (eEF-2K) is an unusual alpha kinase commonly upregulated in various human cancers, including breast, pancreatic, lung, and brain tumors. We have demonstrated that eEF-2K is relevant to poor prognosis and shorter patient survival in breast and lung cancers and validated it as a molecular target using genetic methods in related in vivo tumor models. Although several eEF-2K inhibitors have been published, none of them have shown to be potent and specific enough for translation into clinical trials. Therefore, development of highly effective novel inhibitors targeting eEF-2K is needed for clinical applications. However, currently, the crystal structure of eEF-2K is not known, limiting the efforts for designing novel inhibitor compounds. Therefore, using homology modeling of eEF-2K, we designed and synthesized novel coumarin-3-carboxamides including compounds A1, A2, and B1-B4 and evaluated their activity by performing in silico analysis and in vitro biological assays in breast cancer cells. The Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) area results showed that A1 and A2 have interaction energies with eEF-2K better than those of B1-B4 compounds. Our in vitro results indicated that compounds A1 and A2 were highly effective in inhibiting eEF-2K at 1.0 and 2.5 µM concentrations compared to compounds B1-B4, supporting the in silico findings. In conclusion, the results of this study suggest that our homology modeling along with in silico analysis may be effectively used to design inhibitors for eEF-2K. Our newly synthesized compounds A1 and A2 may be used as novel eEF-2K inhibitors with potential therapeutic applications.

Antiproliferative activity of Humulus lupulus extracts on human hepatoma (Hep3B), colon (HT-29) cancer cells and proteases, tyrosinase, ß-lactamase enzyme inhibition studies.

The aims of this study were to examine the antiproliferation of Humulus lupulus extracts on human hepatoma carcinoma (Hep3B) and human colon carcinoma (HT-29) cell lines along with enzyme inhibitory effects of the crude extracts. Potential cell cytotoxicity of six different H. lupulus extracts were assayed on various cancer cells using MTT assay at 24, 48 and 72 h intervals. Methanol-1 extract has inhibited the cell proliferation with doses of 0.6-1 mg/mL in a time dependent (48 and 72 hours) manner in Hep3B cells with 70% inhibition, while inhibitory effect was not seen in colon cancer cells. Acetone extract has increased the cell proliferation at low doses of 0.1 mg/mL for 72 h in Hep3B cells and 0.1-0.2 mg/mL for 48 and 72 h in HT29 cells. The inhibitory effects of the extracts were compared by relative maximum activity values (V(max)) using proteases such as α-chymotrypsin, trypsin and papain, tyrosinase and ß-lactamase (penicillinase).