scholarly journals Synthesis and Glycosidase Inhibition Properties of Calix[8]arene-Based Iminosugar Click Clusters

2020 ◽  
Vol 13 (11) ◽  
pp. 366
Author(s):  
Jérémy P. Schneider ◽  
Stefano Tommasone ◽  
Paolo Della Sala ◽  
Carmine Gaeta ◽  
Carmen Talotta ◽  
...  

A set of 6- to 24-valent clusters was constructed with terminal deoxynojirimycin (DNJ) inhibitory heads through C6 or C9 linkers by way of Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reactions between mono- or trivalent azido-armed iminosugars and calix[8]arene scaffolds differing in their valency and their rigidity but not in their size. The power of multivalency to upgrade the inhibition potency of the weak DNJ inhibitor (monovalent DNJ Ki being at 322 and 188 µM for C6 or C9 linkers, respectively) was evaluated on the model glycosidase Jack Bean α-mannosidase (JBα-man). Although for the clusters with the shorter C6 linker the rigidity of the scaffold was essential, these parameters had no influence for clusters with C9 chains: all of them showed rather good relative affinity enhancements per inhibitory epitopes between 70 and 160 highlighting the sound combination of the calix[8]arene core and the long alkyl arms. Preliminary docking studies were performed to get insights into the preferred binding modes.

Author(s):  
Suman Rohilla ◽  
Ranju Bansal ◽  
Puneet Chauhan ◽  
Sonja Kachler ◽  
Karl-Norbert Klotz

Background: Adenosine receptors (AR) have emerged as competent and innovative nondopaminergic targets for the development of potential drug candidates and thus constitute an effective and safer treatment approach for Parkinson’s disease (PD). Xanthine derivatives are considered as potential candidates for the treatment Parkinson’s disease due to their potent A2A AR antagonistic properties. Objective: The objectives of the work are to study the impact of substituting N7-position of 8-m/pchloropropoxyphenylxanthine structure on in vitro binding affinity of compounds with various AR subtypes, in vivo antiparkinsonian activity and binding modes of newly synthesized xanthines with A2A AR in molecular docking studies. Methods: Several new 7-substituted 8-m/p-chloropropoxyphenylxanthine analogues have been prepared. Adenosine receptor binding assays were performed to study the binding interactions with various subtypes and perphenazine induced rat catatonia model was used for antiparkinsonian activity. Molecular docking studies were performed using Schrödinger molecular modeling interface. Results: 8-para-substituted xanthine 9b bearing an N7-propyl substituent displayed the highest affinity towards A2A AR (Ki = 0.75 µM) with moderate selectivity versus other AR subtypes. 7-Propargyl analogue 9d produced significantly longlasting antiparkinsonian effects and also produced potent and selective binding affinity towards A2A AR. In silico docking studies further highlighted the crucial structural components required to develop xanthine derived potential A2A AR ligands as antiparkinsonian agents. Conclusion: A new series of 7-substituted 8-m/p-chloropropoxyphenylxanthines having good affinity for A2A AR and potent antiparkinsonian activity has been developed.


2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S25-S26
Author(s):  
Jingjing Ma ◽  
Emma Wu ◽  
Ye Li ◽  
William Seibel ◽  
Le Shen ◽  
...  

Abstract Compromised epithelial barrier function is known to be associated with inflammatory bowel disease (IBD) and may contribute to disease development. One mechanism of barrier dysfunction is increased expression of paracellular tight junction ion and water channels formed by claudins. Claudin-2 and -15 are two such channels. We hypothesize that blocking these channels could be a viable therapeutic approach to treat diarrhea. In an effort to develop blockers of these channels, we turn to our previously developed and validated in silico models of claudin-15 (Samanta et al. 2018). We reasoned that compounds that can bind with the interior of claudin pores can limit paracellular water and ion flux. Thus, we used docking algorithms to search for putative small molecules that bind in the claudin-15 pore. AutoDock Vina was initially used to assess rigid docking using small compound databases. The small molecules were analyzed based on binding affinity to the pore and visualized using VMD for their potential blockage of the channel. Clusters of binding modes were identified based on the prominent interacting residues of the protein with the small molecules. We initially screened 10,500 compounds from within the UIC Centre for Drug Discovery and a cross-section of 10,000 compounds from the NCI open compound repository. This initial screen allowed us to identify 2 first-in-class selective claudin-15 blockers with efficacy in MDCK monolayers induced to express claudin-15 and in wildtype duodenum. Next, we screened the entire NCI open compound repository for additional molecules structurally related to our best initially identified molecule and this has allowed us to identify 13 additional molecules that increase TER of claudin-15 expressing MDCK monolayers by 90–160%. Additionally, these molecules possess similar structural components that will be collected in a fragment library and explored through molecular dynamics simulations. We also developed a claudin-2 homology model on which we are performing docking studies and in vitro measurements, which we expect will result in similar candidate ligands for blocking claudin-2. Our study will provide important insight into the role of claudin-dependent cation permeability in fundamental physiology, which we believe will lead to the utility of claudin blockers as a novel and much needed approach to treat diseases such as IBD.


2020 ◽  
Vol 75 (9-10) ◽  
pp. 353-362
Author(s):  
Begüm Nurpelin Sağlık ◽  
Ahmet Mücahit Şen ◽  
Asaf Evrim Evren ◽  
Ulviye Acar Çevik ◽  
Derya Osmaniye ◽  
...  

AbstractInhibition of aromatase enzymes is very important in the prevention of estrogen-related diseases and the regulation of estrogen levels. Aromatase enzyme is involved in the final stage of the biosynthesis of estrogen, in the conversion of androgens to estrogen. The development of new compounds for the inhibition of aromatase enzymes is an important area for medicinal chemists in this respect. In the present study, new benzimidazole derivatives have been designed and synthesized which have reported anticancer activity in the literature. Their anticancer activity was evaluated against human A549 and MCF-7 cell lines by MTT assay. In the series, concerning MCF-7 cell line, the most potent compounds were the 4-benzylpiperidine derivatives 2c, 2g, and 2k with IC50 values of 0.032 ± 0.001, 0.024 ± 0.001, and 0.035 ± 0.001 µM, respectively, compared to the reference drug cisplatin (IC50 = 0.021 ± 0.001 µM). Then, these compounds were subject to further in silico aromatase enzyme inhibition assays to determine the possible binding modes and interactions underlying their activity. Thanks to molecular docking studies, the effectiveness of these compounds against aromatase enzyme could be simulated. Consequently, it has been found that these compounds can be settled very properly to the active site of the aromatase enzyme.


2021 ◽  
Vol 14 (7) ◽  
pp. 685
Author(s):  
Sandra Amanda Kozieł ◽  
Monika Katarzyna Lesiów ◽  
Daria Wojtala ◽  
Edyta Dyguda-Kazimierowicz ◽  
Dariusz Bieńko ◽  
...  

A group of cytotoxic half-sandwich iridium(III) complexes with aminomethyl(diphenyl)phosphine derived from fluoroquinolone antibiotics exhibit the ability to (i) accumulate in the nucleus, (ii) induce apoptosis, (iii) activate caspase-3/7 activity, (iv) induce the changes in cell cycle leading to G2/M phase arrest, and (v) radicals generation. Herein, to elucidate the cytotoxic effects, we investigated the interaction of these complexes with DNA and serum proteins by gel electrophoresis, fluorescence spectroscopy, circular dichroism, and molecular docking studies. DNA binding experiments established that the complexes interact with DNA by moderate intercalation and predominance of minor groove binding without the capability to cause a double-strand cleavage. The molecular docking study confirmed two binding modes: minor groove binding and threading intercalation with the fluoroquinolone part of the molecule involved in pi stacking interactions and the Ir(III)-containing region positioned within the major or minor groove. Fluorescence spectroscopic data (HSA and apo-Tf titration), together with molecular docking, provided evidence that Ir(III) complexes can bind to the proteins in order to be transferred. All the compounds considered herein were found to bind to the tryptophan residues of HSA within site I (subdomain II A). Furthermore, Ir(III) complexes were found to dock within the apo-Tf binding site, including nearby tyrosine residues.


2018 ◽  
Vol 7 (12) ◽  
pp. 551 ◽  
Author(s):  
Shailima Rampogu ◽  
Doneti Ravinder ◽  
Smita Pawar ◽  
Keun Lee

Cervical cancer is regarded as one of the major burdens noticed in women next to breast cancer. Although, human papilloma viruses (HPVs) are regarded as the principal causative agents, they require certain other factors such as oestrogen hormone to induce cervical cancer. Aromatase is an enzyme that converts androgens into oestrogens and hindering this enzyme could subsequently hamper the formation of oestrogen thereby alleviating the disease. Accordingly, in the current investigation, a structure based pharmacophore was generated considering two proteins bearing the Protein Data Bank (PDB) codes 3EQM (pharm 1) and 3S7S (pharm 2), respectively. The two models were employed as the 3D query to screen the in-house built natural compounds database. The obtained 51 compounds were escalated to molecular docking studies to decipher on the binding affinities and to predict the quintessential binding modes which were affirmed by molecular dynamics (MD) simulations. The compound has induced dose-dependent down regulation of PP2B, Nitric oxide synthase-2 (NOS2), and Interleukin 6 (IL-6) genes in the HeLa cells and has modulated the expression of apoptotic genes such as Bax, Bcl2, and caspases-3 at different concentrations. These results guide us to comprehend that the identified aromatase inhibitor was effective against the cervical cancer cells and additionally could server as scaffolds in designing new drugs.


Author(s):  
Susan Leung ◽  
Michael Bodkin ◽  
Frank von Delft ◽  
Paul Brennan ◽  
Garrett Morris

One of the fundamental assumptions of fragment-based drug discovery is that the fragment’s binding mode will be conserved upon elaboration into larger compounds. The most common way of quantifying binding mode similarity is Root Mean Square Deviation (RMSD), but Protein Ligand Interaction Fingerprint (PLIF) similarity and shape-based metrics are sometimes used. We introduce SuCOS, an open-source shape and chemical feature overlap metric. We explore the strengths and weaknesses of RMSD, PLIF similarity, and SuCOS on a dataset of X-ray crystal structures of paired elaborated larger and smaller molecules bound to the same protein. Our redocking and cross-docking studies show that SuCOS is superior to RMSD and PLIF similarity. When redocking, SuCOS produces fewer false positives and false negatives than RMSD and PLIF similarity; and in cross-docking, SuCOS is better at differentiating experimentally-observed binding modes of an elaborated molecule given the pose of its non-elaborated counterpart. Finally we show that SuCOS performs better than AutoDock Vina at differentiating actives from decoy ligands using the DUD-E dataset. SuCOS is available at https://github.com/susanhleung/SuCOS . <br>


2019 ◽  
Author(s):  
Susan Leung ◽  
Michael Bodkin ◽  
Frank von Delft ◽  
Paul Brennan ◽  
Garrett Morris

One of the fundamental assumptions of fragment-based drug discovery is that the fragment’s binding mode will be conserved upon elaboration into larger compounds. The most common way of quantifying binding mode similarity is Root Mean Square Deviation (RMSD), but Protein Ligand Interaction Fingerprint (PLIF) similarity and shape-based metrics are sometimes used. We introduce SuCOS, an open-source shape and chemical feature overlap metric. We explore the strengths and weaknesses of RMSD, PLIF similarity, and SuCOS on a dataset of X-ray crystal structures of paired elaborated larger and smaller molecules bound to the same protein. Our redocking and cross-docking studies show that SuCOS is superior to RMSD and PLIF similarity. When redocking, SuCOS produces fewer false positives and false negatives than RMSD and PLIF similarity; and in cross-docking, SuCOS is better at differentiating experimentally-observed binding modes of an elaborated molecule given the pose of its non-elaborated counterpart. Finally we show that SuCOS performs better than AutoDock Vina at differentiating actives from decoy ligands using the DUD-E dataset. SuCOS is available at https://github.com/susanhleung/SuCOS . <br>


Author(s):  
Sanchaita Rajkhowa ◽  
Ramesh C. Deka

Molecular docking is a key tool in structural biology and computer-assisted drug design. Molecular docking is a method which predicts the preferred orientation of a ligand when bound in an active site to form a stable complex. It is the most common method used as a structure-based drug design. Here, the authors intend to discuss the various types of docking methods and their development and applications in modern drug discovery. The important basic theories such as sampling algorithm and scoring functions have been discussed briefly. The performances of the different available docking software have also been discussed. This chapter also includes some application examples of docking studies in modern drug discovery such as targeted drug delivery using carbon nanotubes, docking of nucleic acids to find the binding modes and a comparative study between high-throughput screening and structure-based virtual screening.


Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1789 ◽  
Author(s):  
Julia Krzywik ◽  
Witold Mozga ◽  
Maral Aminpour ◽  
Jan Janczak ◽  
Ewa Maj ◽  
...  

Colchicine is a well-known compound with strong antiproliferative activity that has had limited use in chemotherapy because of its toxicity. In order to create more potent anticancer agents, a series of novel colchicine derivatives have been obtained by simultaneous modification at C7 (amides and sulfonamides) and at C10 (methylamino group) positions and characterized by spectroscopic methods. All the synthesized compounds have been tested in vitro to evaluate their cytotoxicity toward A549, MCF-7, LoVo, LoVo/DX and BALB/3T3 cell lines. Additionally, the activity of the studied compounds was investigated using computational methods involving molecular docking of the colchicine derivatives to β-tubulin. The majority of the obtained derivatives exhibited higher cytotoxicity than colchicine, doxorubicin or cisplatin against tested cancer cell lines. Furthermore, molecular modeling studies of the obtained compounds revealed their possible binding modes into the colchicine binding site of tubulin.


Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2213 ◽  
Author(s):  
Alessandro Dessì ◽  
Paola Peluso ◽  
Roberto Dallocchio ◽  
Robin Weiss ◽  
Giuseppina Andreotti ◽  
...  

The 3,3′,5,5′-tetrachloro-2-iodo-4,4′-bipyridine structure is proposed as a novel chemical scaffold for the design of new transthyretin (TTR) fibrillogenesis inhibitors. In the frame of a proof-of-principle exploration, four chiral 3,3′,5,5′-tetrachloro-2-iodo-2′-substituted-4,4′- bipyridines were rationally designed and prepared from a simple trihalopyridine in three steps, including a Cu-catalysed Finkelstein reaction to introduce iodine atoms on the heteroaromatic scaffold, and a Pd-catalysed coupling reaction to install the 2′-substituent. The corresponding racemates, along with other five chiral 4,4′-bipyridines containing halogens as substituents, were enantioseparated by high-performance liquid chromatography in order to obtain pure enantiomer pairs. All stereoisomers were tested against the amyloid fibril formation (FF) of wild type (WT)-TTR and two mutant variants, V30M and Y78F, in acid mediated aggregation experiments. Among the 4,4′-bipyridine derivatives, interesting inhibition activity was obtained for both enantiomers of the 3,3′,5,5′-tetrachloro-2′-(4-hydroxyphenyl)-2-iodo-4,4′-bipyridine. In silico docking studies were carried out in order to explore possible binding modes of the 4,4′-bipyridine derivatives into the TTR. The gained results point out the importance of the right combination of H-bond sites and the presence of iodine as halogen-bond donor. Both experimental and theoretical evidences pave the way for the utilization of the iodinated 4,4′-bipyridine core as template to design new promising inhibitors of TTR amyloidogenesis.


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