CycloSiFA: The Next Generation of Silicon-Based Fluoride Acceptors for Positron Emission Tomography (PET).

The ring-opening Si-fluorination of a variety of azasilole derivatives cyclo-1-(iPr2 Si)-4-X-C6 H3 -2-CH2 NR (4: R=2,6-iPr2 C6 H3 , X=H; 4 a: R=2,4,6-Me3 C6 H2 , X=H; 9: R=2,6-iPr2 C6 H3 , X=tBuMe2 SiO; 10: R=2,6-iPr2 C6 H3 , X=OH; 13: R=2,6-iPr2 C6 H3 , X=HCCCH2 O; 22: R=2,6-iPr2 C6 H3 , X=tBuMe2 SiCH2 O) with different 19 F-fluoride sources was studied, optimized and the experience gained was used in a translational approach to create a straightforward 18 F-labelling protocol for the azasilole derivatives [18 F]6 and [18 F]14. The latter constitutes a potential clickable CycloSiFA prosthetic group which might be used in PET tracer development using Cu-catalysed triazole formation. Based on our findings, CycloSiFA has the potential to become a new entry into non-canonical labelling methodologies for radioactive PET tracer development.

Recent Advances in the Clinical Translation of Silicon Fluoride Acceptor (SiFA) 18F-Radiopharmaceuticals.

The incorporation of silicon fluoride acceptor (SiFA) moieties into a variety of molecules, such as peptides, proteins and biologically relevant small molecules, has improved the generation of 18F-radiopharmaceuticals for medical imaging. The efficient isotopic exchange radiofluorination process, in combination with the enhanced [18F]SiFA in vivo stability, make it a suitable strategy for fluorine-18 incorporation. This review will highlight the clinical applicability of [18F]SiFA-labeled compounds and discuss the significant radiotracers currently in clinical use.

Discovery of novel wee1 inhibitors via structure-based virtual screening and biological evaluation.

Wee1 plays a critical role in the arrest of G2/M cell cycle for DNA repair before entering mitosis. Many cancer cells have been identified as overexpression of Wee1. In this research, pharmacophore modeling, molecular docking and molecular dynamics simulation approaches were constructed to identify novel potential Wee1 inhibitors. A compound 8 was found to have a novel skeleton against Wee1 with an IC50 value of 22.32 µM and a Ki value of 13.11 µM. Kinetic assays were employed to evaluate the compound 8 as a competitive inhibitor. Compound 8 was tested against A-549 tumor cell lines with IC50 value of 17.8 µM. To investigate the intermolecular interaction of Wee1 and compound 8, further molecular dynamics simulations were performed. It indicates that the binding mode of compound 8 and reference ligand is similar. The active core scaffold of compound 8 could represent a promising lead compound for studying Wee1 and be used for further structural optimization to design more potent Wee1 inhibitors.

In silico Discovery of Novel FXa Inhibitors by Pharmacophore Modeling and Molecular Docking.

Coagulation Factor Xa (FXa) is the crucial enzyme at the convergent point of the intrinsic and extrinsic coagulation pathways. The inhibition of FXa is an effective approach against thrombotic diseases. In the present study, a specific strategy is reported to discover 10 novel FXa inhibitors based on ligand-based (pharmacophore) virtual screening and molecular docking analysis from a dataset of specs(containing 220000 molecules). The binding modes analysis provide insights into the contribution of particular structural moieties of the compounds towards their activity against FXa, and 10 novel structural compounds were discovered as potent candidate molecules. This work could be helpful in further design and development of FXa inhibitors.

Comparative QSAR studies using HQSAR, CoMFA, and CoMSIA methods on cyclic sulfone hydroxyethylamines as BACE1 inhibitors.

The inhibition of ß-secretase (BACE1) is currently the main pharmacological strategy available for Alzheimer's disease (AD). 2D QSAR and 3D QSAR analysis on some cyclic sulfone hydroxyethylamines inhibitors against ß-secretase (IC50: 0.002-2.75µM) were carried out using hologram QSAR (HQSAR), comparative molecular field analysis (CoMFA), and comparative molecular similarity indices analysis (CoMSIA) methods. The best model based on the training set was generated with a HQSAR q2 value of 0.693 and r2 value of 0.981; a CoMFA q2 value of 0.534 and r2 value of 0.913; and a CoMSIA q2 value of 0.512 and r2 value of 0.973. In order to gain further understand of the vital interactions between cyclic sulfone hydroxyethylamines and the protease, the analysis was performed by combining the CoMFA and CoMSIA field distributions with the active sites of the BACE1. The final QSAR models could be helpful in the design and development of novel active BACE1 inhibitors.

Discovery of new dual binding TNKS inhibitors of Wnt signaling inhibition by pharmacophore modeling, molecular docking and bioassay.

Tankyrases (TNKS), key transmitters in the Wnt signaling pathway which is very conservative in evolution, are vital targets as they are overexpressed widely in many cancers. In this work, 5 inhibitors with novel structures have been discovered and validated using the ligand-based (pharmacophore) virtual screening, docking study, and Luciferase reporter assays for Wnt signaling. Among them, PYL-1, in particular, was the most potent inhibitor with an IC50 value of 9.56 µM against Wnt signaling. The analysis of binding modes was performed to further understand the vital interactions between inhibitors and TNKS 2, and the five hits belong to dual site inhibitors. This work could be helpful for the design and development of novel dual binders as TNKS inhibitors.

The discovery of new acetylcholinesterase inhibitors derived from pharmacophore modeling, virtual screening, docking simulation and bioassays.

Hyperactivity of acetylcholinesterase (AChE) in the brain is the immediate cause of Alzheimer's disease (AD), which is one of the most prevalent fatal diseases afflicting numerous older people. In this research, an in silico study was carried out to find potential AChE inhibitors from a large chemical library. With clustering and lots of comprehensive analysis, some molecules were screened using in vitro bioassays. The IC50 values against AChE ranged from 33.620 to 101.570 µM, while the inhibition ratios at 50 µM ranged from 11.37% to 77.35%. The binding mode between the inhibitor and the binding sites of AChE was studied. Four residues (Tyr133, Tyr124, Ser203 and Trp86) were suggested to be crucial because they can form hydrogen bonds with the ligand. Therefore, ZYQ1 and its derivatives might represent a promising starting point for the development of highly potent lead compounds for the treatment of AD.