Identification of Enzyme Inhibitors Using Therapeutic Target Protein - Magnetic Nanoparticle Conjugates

Discovery of ellagic acid as a competitive inhibitor of Src homology phosphotyrosyl phosphatase 2 (SHP2) for cancer treatment: In vitro and in silico study

Targeting SHP2 has become a potential cancer treatment strategy. In this study, ellagic acid was first reported as a competitive inhibitor of SHP2, with an IC50 value of 0.69 ± 0.07 μM, and its inhibitory potency was 34.86 times higher that of the positive control NSC87877. Ellagic acid also had high inhibitory activity on the SHP2-E76K and SHP2-E76A mutants, with the IC50 values of 1.55 ± 0.17 μM and 0.39 ± 0.05 μM, respectively. Besides, the IC50 values of ellagic acid on homologous proteins SHP1, PTP1B, and TCPTP were 0.93 ± 0.08 μM, 2.04 ± 0.28 μM, and 11.79 ± 0.83 μM, with selectivity of 1.35, 2.96, and 17.09 times, respectively. The CCK8 proliferation experiment exhibited that ellagic acid would inhibit the proliferation of various cancer cells. It was worth noting that the combination of ellagic acid and KRASG12C inhibitor AMG510 would produce a strong synergistic effect in inhibiting NCI-H358 cells. Western blot experiment exhibited that ellagic acid would downregulate the phosphorylation levels of Erk and Akt in NCI-H358 and MDA-MB-468 cells. Molecular docking and molecular dynamics studies revealed the binding information between SHP2 and ellagic acid. In summary, this study provides new ideas for the development of SHP2 inhibitors.

Immobilized enzyme for screening and identification of anti-diabetic components from natural products by ligand fishing

Diabetes is a chronic metabolic disease caused by insufficient insulin secretion and insulin resistance. Natural product is one of the most important resources for anti-diabetic drug. However, due to the extremely complex composition, this research is facing great challenges. After the advent of ligand fishing technology based on enzyme immobilization, the efficiency of screening anti-diabetic components has been greatly improved. In order to provide critical knowledge for future research in this field, the application progress of immobilized enzyme in screening anti-diabetic components from complex natural extracts in recent years was reviewed comprehensively, including novel preparation technologies and strategies of immobilized enzyme and its outstanding application prospect in many aspects. The basic principles and preparation steps of immobilized enzyme were briefly described, including entrapment, physical adsorption, covalent binding, affinity immobilization, multienzyme system and carrier-free immobilization. New formatted immobilized enzymes with different carriers, hollow fibers, magnetic materials, microreactors, metal organic frameworks, etc., were widely used to screen anti-diabetic compositions from various natural products, such as Ginkgo biloba, Morus alba, lotus leaves, Pueraria lobata, Prunella vulgaris, and Magnolia cortex. Furthermore, the challenges and future prospects in this field were put forward in this review.

Tyrosinase covalently immobilized on carboxyl functionalized magnetic nanoparticles for fishing of the enzyme's ligands from Prunellae Spica

In this study, tyrosinase was immobilized on carboxyl functionalized silica-coated magnetic nanoparticles for the first time to be used for fishing of tyrosinase's ligands present in complex plant extract. The immobilized tyrosinase was characterized by transmission electron microscopy, vibrating sample magnetometry, Fourier transform infrared spectroscopy, thermo-gravimetric analyzer, and atomic force microscopy. The reusability and thermostability of the immobilized tyrosinase were found significantly superior to its free counterpart. Two tyrosinase's ligands, that is, caffeic acid (1) and rosmarinic acid (2), were fished out from extract of the traditional Chinese medicine Prunellae Spica by the immobilized tyrosinase. Compound 1 was found to be an activator of the enzyme with the half maximal effective concentration value of 0.27 ± 0.06 mM, while compound 2 was an inhibitor with the half maximal inhibitory concentration value of 0.14 ± 0.03 mM. Taking advantage of the convenience of magnetic separation and specific extraction ability of ligand fishing, the proposed method exhibited great potential for screening of bioactive compounds from complex matrices.

Magnetic particles for enzyme immobilization: A versatile support for ligand screening

Enzyme inhibitors represent a substantial fraction of all small molecules currently in clinical use. Therefore, the early stage of drug-discovery process and development efforts are focused on the identification of new enzyme inhibitors through screening assays. The use of immobilized enzymes on solid supports to probe ligand-enzyme interactions have been employed with success not only to identify and characterize but also to isolate new ligands from complex mixtures. Between the available solid supports, magnetic particles have emerged as a promising support for enzyme immobilization due to the high superficial area, easy separation from the reaction medium and versatility. Particularly, the ligand fishing assay has been employed as a very useful tool to rapidly isolate bioactive compounds from complex mixtures, and hence the use of magnetic particles for enzyme immobilization has been widespread. Thus, this review provides a critical overview of the screening assays using immobilized enzymes on magnetic particles between 2006 and 2021.

Micro- and nano-sized amine-terminated magnetic beads in a ligand fishing assay

Functionalized micro- and nano-sized magnetic beads (MBs) have been widely used as versatile supports for proteins, enzymes, and drugs. Immobilized protein on MB surfaces has been successfully applied for ligand fishing assays allowing for direct identification of active ligands from complex mixtures, such as natural products and synthetic libraries. MBs with different properties such as different core compositions, sizes, coatings, and surface modifications are available commercially. Studies have been conducted to understand the role of these properties for ligand fishing assays. Here we evaluated, for the first time, the effect of MB size on the ligand fishing assay for acetylcholinesterase from Electrophorus electricus (AChE). For this purpose, four commercially available amine-terminated magnetic particles with diameters ranging from 4.5 nm to 106 μm were evaluated to fish out galantamine, a well-known AChE inhibitor, from an aqueous solution. All MBs were efficient at using glutaraldehyde to covalently immobilize AChE. The particles with diameters of about 1 μm (small microparticles) presented a higher protein mass capacity per milligram of particle than did those with diameters of about 4.5 nm (nanoparticles) and those with diameters of about 106 μm (large microparticles). The influence of these supports on the produced AChE-MBs with regards to hydrolysis turnover and ligand fishing was evaluated and is fully discussed.

Rapid identification of α-glucosidase inhibitors from Dioscorea opposita Thunb peel extract by enzyme functionalized Fe3O4 magnetic nanoparticles coupled with HPLC-MS/MS

Two α-glucosidase inhibitors identified as 2,4-dimethoxy-6,7-dihydroxyphenanthrene and batatasin I were conveniently extracted from Dioscorea opposita Thunb peel extract using αG-MNPs.

Screening for the bioactive constituents of traditional Chinese medicines—progress and challenges

The search for lead compounds from traditional Chinese medicines (TCMs) may be promising for new drug development.

Comparison of analytical techniques for the identification of bioactive compounds from natural products

Covering: 2000 to 2016Natural product extracts are a rich source of bioactive compounds. As a result, the screening of natural products for the identification of novel biologically active metabolites has been an essential part of several drug discovery programs. It is estimated that more than 70% of all drugs approved from 1981 and 2006, were either derived from or structurally similar to nature based compounds indicating the necessity for the development of a rapid method for the identification of novel compounds from plant extracts. The screening of biological matrices for the identification of novel modulators is nevertheless still challenging. In this review we discuss current techniques in phytochemical analysis and the identification of biologically active components.

A Rapid Study of Botanical Drug–Drug Interaction with Protein by Re-ligand Fishing using Human Serum Albumin–Functionalized Magnetic Nanoparticles

A great many active constituents of botanical drugs bind to human serum albumin (HSA) reversibly with a dynamic balance between the free- and bound-forms in blood. The curative or side effect of a drug depends on its free-form level, which is always influenced by other drugs, combined dosed or multi-constituents of botanical drugs. This paper presented a rapid and convenient methodology to investigate the drug-drug interactions with HSA. The interaction of two steroidal saponins, dioscin and pseudo-protodioscin, from a botanical drug was studied for their equilibrium time and equilibrium amount by re-ligand fishing using HSA functionalized magnetic nanoparticles. A clear competitive situation was obtained by this method. The equilibrium was reached soon about 15 s at a ratio of 0.44: 1. Furthermore, the interaction of pseudo-protodioscin to total steroidal saponins from DAXXK was also studied. The operation procedures of this method were faster and more convenient compared with other methods reported.

Polymer–nanoparticles composites in bioanalytical sample preparation

The term composite refers to a class of synthetic materials made from different constituents which exhibit final properties which are different from those of the individual components. Composites have been extensively used in the sample treatment context as sorbents since the resulting solid presents better extraction efficiency. In this realm, polymeric nanocomposites are raised as a powerful alternative. They can be tailored-synthesized for selectivity enhancement or include a magnetic core to simplify the extraction/elution process. This review article points out the relevance of such nanomaterials in bioanalysis. Several synergic combinations of nanoparticles (magnetic, carbon-based) as well as polymeric coatings (conventional, conductive or molecularly imprinted) are commented on. Finally, the potential of biopolymers in the microextraction field is briefly highlighted.

Metabolic study of Angelica dahurica extracts using a reusable liver microsomal nanobioreactor by liquid chromatography-mass spectrometry

Highly active and recoverable nanobioreactors prepared by immobilizing rat liver microsomes on magnetic nanoparticles (LMMNPs) were utilized in metabolic study of Angelica dahurica extracts. Five metabolites were detected in the incubation solution of the extracts and LMMNPs, which were identified by means of HPLC-MS as trans-imperatorin hydroxylate (M1), cis-imperatorin hydroxylate (M2), imperatorin epoxide (M3), trans-isoimperatorin hydroxylate (M1') and cis-isoimperatorin hydroxylate (speculated M2'). Compared with the metabolisms of imperatorin and isoimperatorin, it was found that the five metabolites were all transformed from these two major compounds present in the plant. Since no study on isoimperatorin metabolism by liver microsomal enzyme system has been reported so far, its metabolites (M1' and M3') were isolated by preparative HPLC for structure elucidation by (1) H-NMR and MS(2) analysis. M3' was identified as isoimperatorin epoxide, which is a new compound as far as its chemical structure is concerned. However, interestingly, M3' was not detected in the metabolism of the whole plant extract. In addition, a study with known chemical inhibitors on individual isozymes of the microsomal enzyme family revealed that CYP1A2 is involved in metabolisms of both isoimperatorin and imperatorin, and CYP3A4 only in that of isoimperatorin.

Lipase ligands in Nelumbo nucifera leaves and study of their binding mechanism

Lotus (Nelumbo nucifera) leaves have been widely used in weight-loss foods to prevent obesity in China. In this work, a facile procedure based on ligand fishing was developed to isolate and identify lipase inhibitors present in lotus leaves. Highly stable and active lipase-Fe3O4 superparamagnetic nanoparticle conjugates (LMNPs) were prepared and used as baits. Two flavonoids in lotus leaf extract were found to bind to the baits and were identified as quercetin-3-O-β-d-arabinopyranosyl-(1→2)- β-d-galactopyranoside (1) and quercetin-3-O-β-d-glucuronide (4) based on electrospray ionization-mass spectrometric analyses. Their 50% inhibitory concentrations on lipase (IC50) were 52.9 ± 3.2 and 17.1 ± 1.5 μg/mL, respectively. In addition, they were found to significantly quench the fluorescence of lipase, suggesting their strong affinities with this enzyme, which was further evidenced by molecular docking. Ligand fishing based on LMNPs shows great power for fast screening and identification of lipase inhibitors present in edible and medicinal plants.