Design, synthesis, and biological evaluation of novel phenol ether derivatives as non-covalent proteasome inhibitors

Facile synthesis of FeCeOx nanoparticles encapsulated carbon nitride catalyst for highly efficient and recyclable synthesis of substituted imidazoles

Herein, we developed a novel composite called FeCeOx@g-C3N4 through a combination of sonication, sintering, and hydrothermal techniques to implement the principles of green chemistry by utilizing reusable nanocomposites in one-pot reactions. To gain a comprehensive understanding of the catalyst's structure, composition, and morphology, various characterization methods were employed. These included FT-IR analysis to examine chemical bonds, SEM and TEM imaging to visualize the catalyst's surface and internal structure, TGA to assess thermal stability, EDS for elemental composition analysis, and XRD to determine crystal structure. The FeCeOx@g-C3N4 nanocatalyst demonstrated remarkable efficacy in the one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazole. Noteworthy features of this catalyst included high percentage yield, mild reaction conditions, short reaction time, and an efficient and straightforward procedure. Furthermore, the FeCeOx@g-C3N4 composite exhibited excellent recyclability and reusability. It could be recycled and reused up to four times without a significant decline in catalytic activity.

Design, synthesis, and biological evaluation of some novel naphthoquinone-glycine/β-alanine anilide derivatives as noncovalent proteasome inhibitors

A series of novel noncovalent glycine/β-alanine anilide derivatives possessing 2-chloronaphthoquinone structure as a pharmacophoric unit were designed, synthesized, and evaluated for their antiproliferative and antiproteasomal activities against MCF-7 cell line, in vitro. According to biological activity results, all the target compounds showed antiproliferative activity in the range of IC₅₀  = 7.10 ± 0.10-41.08 ± 0.14 μM and most of them exhibited inhibitory efficacy with varying ratios against the three catalytic subunits (β1, β2, and β5) presenting caspase-like (C-L), trypsin-like (T-L) and chymotrypsin-like (ChT-L) activities of proteasome. The antiproteasomal activity evaluations revealed that compounds preferentially inhibited the β5 subunit compared with β1 and β2 subunits of the proteasome. Among the compounds, compounds 7 and 9 showed the highest antiproliferative activity with an IC₅₀ value of 7.10 ± 0.10 and 7.43 ± 0.25 μM, respectively. Additionally, compound 7 displayed comparable potency to PI-083 lead compound in terms of β5 antiproteasomal activity with an inhibition percentage of 34.67 at 10 μM. This compound showed an IC₅₀ value of 32.30 ± 0.45 μM against β5 subunit. Furthermore, molecular modeling studies of the most active compound 7 revealed key interactions with β5 subunit. The results suggest that this class of compounds may be beneficial for the development of new potent proteasome inhibitors.

Terminal Phenoxy Group as a Privileged Moiety of the Drug Scaffold-A Short Review of Most Recent Studies 2013-2022

The terminal phenoxy group is a moiety of many drugs in use today. Numerous literature reports indicated its crucial importance for biological activity; thus, it is a privileged scaffold in medicinal chemistry. This review focuses on the latest achievements in the field of novel potential agents bearing a terminal phenoxy group in 2013-2022. The article provided information on neurological, anticancer, potential lymphoma agent, anti-HIV, antimicrobial, antiparasitic, analgesic, anti-diabetic as well as larvicidal, cholesterol esterase inhibitors, and antithrombotic or agonistic activities towards the adrenergic receptor. Additionally, for selected agents, the Structure-Activity-Relationship (SAR) is also discussed. Thus, this study may help the readers to better understand the nature of the phenoxy group, which will translate into rational drug design and the development of a more efficient drug. To the best of our knowledge, this is the first review devoted to an in-depth analysis of the various activities of compounds bearing terminal phenoxy moiety.

Metabolism guided optimization of peptidomimetics as non-covalent proteasome inhibitors for cancer treatment

A series of novel non-covalent peptidomimetic proteasome inhibitors possessing bulky group at the C-terminus and N-alkylation at the N-terminus were designed with the aim to increase metabolic stabilities in vivo. All the target compounds were screened for their inhibitory activities against human 20S proteasome, and most analogs exhibited notable potency compared with the positive control bortezomib with IC₅₀ values lower than 10 nM, which also displayed potent cytotoxic activities against multiple myeloma (MM) cell lines and human acute myeloid leukemia (AML) cells. Furthermore, whole blood stability and in vivo proteasome inhibitory activity experiments of selected compounds were conducted for further evaluation, and the representative compound 43 (IC₅₀ = 8.39 ± 2.32 nM, RPMI-8226: IC₅₀ = 15.290 ± 2.281 nM, MM-1S: IC₅₀ = 9.067 ± 3.103 nM, MV-4-11: IC₅₀ = 2.464 ± 0.713 nM) revealed a half-life extension of greater than 9-fold (329.21 min VS 36.79 min) and potent proteasome inhibitory activity in vivo. The positive results confirmed the reliability of the metabolism guided optimization strategy, and the analogs discovered are potential leads for exploring new anti-MM drugs.

Nitazoxanide and related thiazolides induce cell death in cancer cells by targeting the 20S proteasome with novel binding modes

Nitazoxanide and related thiazolides are a novel class of anti-infectious agents against protozoan parasites, bacteria and viruses. In recent years, it is demonstrated thatthiazolides also can induced cell cycle arrest and apoptotic cell death in cancer cells. Due to their fast proliferating nature, cancer cells highly depend on the proteasome system to remove aberrant proteins. Many of these aberrant proteins are regulators of cell cycle progression and apoptosis, such as the cyclins, BCL2 family members and nuclear factor of κB (NF-κB). Here, we demonstrate at both molecular and cellular levels that the 20S proteasome is a direct target of NTZ and other thiazolides. By concurrently inhibiting the multiple catalytic subunits of 20S proteasome, NTZ promotes cell cycle arrest and triggers cell death in colon cancer cells, either directly or a sensitizer to other anti-tumor agents, especially doxorubicin. We further show that the binding mode of NTZ in the β5 subunit of the 20S proteasome is different from that of bortezomib and other existing proteasome inhibitors. These findings provide new insights in the design of novel small molecular proteasome inhibitors as anti-tumor agents suitable for solid tumor treatment in an oral dosing form.

Diaryl azo derivatives as anti-diabetic and antimicrobial agents: synthesis, in vitro, kinetic and docking studies

In the present study, a series of azo derivatives (TR-1 to TR-9) have been synthesised via the diazo-coupling approach between substituted aromatic amines with phenol or naphthol derivatives. The compounds were evaluated for their therapeutic applications against alpha-glucosidase (anti-diabetic) and pathogenic bacterial strains E. coli (gram-negative), S. aureus (gram-positive), S. aureus (gram-positive) drug-resistant strain, P. aeruginosa (gram-negative), P. aeruginosa (gram-negative) drug-resistant strain and P. vulgaris (gram-negative). The IC₅₀ (µg/mL) of TR-1 was found to be most effective (15.70 ± 1.3 µg/mL) compared to the reference drug acarbose (21.59 ± 1.5 µg/mL), hence, it was further selected for the kinetic studies in order to illustrate the mechanism of inhibition. The enzyme inhibitory kinetics and mode of binding for the most active inhibitor (TR-1) was performed which showed that the compound is a non-competitive inhibitor and effectively inhibits the target enzyme by binding to its binuclear active site reversibly.

Chemical Patterns of Proteasome Inhibitors: Lessons Learned from Two Decades of Drug Design

Drug discovery now faces a new challenge, where the availability of experimental data is no longer the limiting step, and instead, making sense of the data has gained a new level of importance, propelled by the extensive incorporation of cheminformatics and bioinformatics methodologies into the drug discovery and development pipeline. These enable, for example, the inference of structure-activity relationships that can be useful in the discovery of new drug candidates. One of the therapeutic applications that could benefit from this type of data mining is proteasome inhibition, given that multiple compounds have been designed and tested for the last 20 years, and this collection of data is yet to be subjected to such type of assessment. This study presents a retrospective overview of two decades of proteasome inhibitors development (680 compounds), in order to gather what could be learned from them and apply this knowledge to any future drug discovery on this subject. Our analysis focused on how different chemical descriptors coupled with statistical tools can be used to extract interesting patterns of activity. Multiple instances of the structure-activity relationship were observed in this dataset, either for isolated molecular descriptors (e.g., molecular refractivity and topological polar surface area) as well as scaffold similarity or chemical space overlap. Building a decision tree allowed the identification of two meaningful decision rules that describe the chemical parameters associated with high activity. Additionally, a characterization of the prevalence of key functional groups gives insight into global patterns followed in drug discovery projects, and highlights some systematically underexplored parts of the chemical space. The various chemical patterns identified provided useful insight that can be applied in future drug discovery projects, and give an overview of what has been done so far.