Protein-ligand interaction-guided discovery of novel VEGFR-2 inhibitors

Research and development of N,N'-diarylureas as anti-tumor agents

Tumor neovascularization provides abundant nutrients for the occurrence and development of tumors, and is also an important factor in tumor invasion and metastasis, which has attracted extensive attention in anti-tumor therapy. Sorafenib is a clinically approved multi-targeted anti-tumor drug that targets vascular endothelial growth factor receptor (VEGFR) and inhibits the formation of tumor angiogenesis, thereby achieving the purpose of suppressing tumor growth. Since the approval of sorafenib, N,N'-diarylureas have received extensive attention as the key pharmacophore in its chemical structure. And a series of N,N'-diarylureas were designed and synthesized to screen a new generation of anti-tumor drug candidates through chemical modification and structural optimization. Moreover, the rational design of targeted drugs is beneficial to reduce toxic side effects and drug resistance and improve the curative effect. Here, this article reviews the research progress in the design, classification, structure-activity relationship (SAR) and biological activity of N,N'-diarylureas, in order to provide some prospective routes for the development of clinically effective anti-tumor drugs.

Effect of pH on Diclofenac–Lysozyme Interaction: Structural and Functional Aspect

As a nonsteroidal antiinflammatory drug, diclofenac (DCF) is used in the treatment of a variety of human ailments. It has already been reported that the use of this class of drugs for a longer duration is associated with numerous side effects such as cardiovascular implications, reno-medullary complications, etc. In the present study, the effect of DCF on the structure, stability, and function of lysozyme was studied. The study was designed to examine the effect of DCF only at various pH values. Heat-induced denaturation of lysozyme was analyzed in the presence and absence of various molar concentrations of DCF at different pH values. The values of thermodynamic parameters, the midpoint of denaturation (T_m), enthalpy change at T_m (ΔH_m), constant pressure heat capacity change (ΔC_p), and Gibbs energy change at 25°C (ΔG_D^o), thus obtained under a given set of conditions (pH and molar concentration of DCF), demonstrated the following 1) DCF destabilized lysozyme with respect of T_m and ΔG_D^o at all the pH values, 2) the magnitude of protein destabilization is lesser at acidic pH than at physiological pH, 3) structural changes in lysozyme are less projecting at pH 2.0 than at pH 7.0, and 4) quenching is observed at both pH values. Furthermore, the process of protein destabilization in the presence of DCF is entropically driven.

Target-based anticancer indole derivatives and insight into structure‒activity relationship: A mechanistic review update (2018‒2021)

Cancer, which is the uncontrolled growth of cells, is the second leading cause of death after heart disease. Targeting drugs, especially to specific genes and proteins involved in growth and survival of cancer cells, is the prime need of research world-wide. Indole moiety, which is a combination of aromatic-heterocyclic compounds, is a constructive scaffold for the development of novel leads. Owing to its bioavailability, high unique chemical properties and significant pharmacological behaviours, indole is considered as the most inquisitive scaffold for anticancer drug research. This is illustrated by the fact that the U.S. Food and Drug Administration (FDA) has recently approved several indole-based anticancer agents such as panobinostat, alectinib, sunitinib, osimertinib, anlotinib and nintedanib for clinical use. Furthermore, hundreds of studies on the synthesis and activity of the indole ring have been published in the last three years. Taking into account the facts stated above, we have presented the most recent advances in medicinal chemistry of indole derivatives, encompassing hot articles published between 2018 and 2021 in anticancer drug research. The recent advances made towards the synthesis of promising indole-based anticancer compounds that may act via various targets such as topoisomerase, tubulin, apoptosis, aromatase, kinases, etc., have been discussed. This review also summarizes some of the recent efficient green chemical synthesis for indole rings using various catalysts for the period during 2018–2021. The review also covers the synthesis, structure‒activity relationship, and mechanism by which these leads have demonstrated improved and promising anticancer activity. Indole molecules under clinical and preclinical stages are classified into groups based on their cancer targets and presented in tabular form, along with their mechanism of action. The goal of this review article is to point the way for medicinal chemists to design and develop effective indole-based anticancer agents.

Recent advances in, and challenges of, anti-angiogenesis agents for tumor chemotherapy based on vascular normalization

A major problem associated with cancer treatment is resistance-prone chemotherapeutic drugs. An increasing number of studies have documented that the occurrence of resistance tends to be associated with abnormal blood vessels. In 2001, Jain proposed the vascular normalization theory, which was recently applied to the drug-resistant treatment of tumors in the clinic. Through the intervention of angiogenesis inhibitors, remodeling the structure and function of abnormal vessels can maximize the efficacy of chemotherapeutic drugs. In this review, we systematically describe the occurrence and progress of tumor angiogenesis, as well as the pathological characteristics of tumor blood vessels. Moreover, druggable targets for vascular normalization and the development of related inhibitors are also outlined.

Synthesis and Rational Design of New Appended 1,2,3-Triazole-uracil Ensembles as Promising Anti-Tumor Agents via In Silico VEGFR-2 Transferase Inhibition

Angiogenesis inhibition is a key step towards the designing of new chemotherapeutic agents. In a view to preparing new molecular entities for cancer treatment, eighteen 1,2,3-triazole-uracil ensembles 5a-r were designed and synthesized via the click reaction. The ligands were well characterized using 1H-, 13C-NMR, elemental analysis and ESI-mass spectrometry. The in silico binding propinquities of the ligands were studied sequentially in the active region of VEGFR-2 using the Molegro virtual docker. All the compounds produced remarkable interactions and potentially inhibitory ligands against VEGFR-2 were obtained with high negative binding energies. Drug-likeness was assessed from the ADME properties. Cytotoxicity of the test compounds was measured against HeLa and HUH-7 tumor cells and NIH/3T3 normal cells by MTT assay. Compound 5h showed higher growth inhibition activity than the positive control, 5-fluorouracil (5-FU), against both HeLa and HUH-7 cells with IC50 values of 4.5 and 7.7 μM respectively. Interestingly, the compounds 5a-r did not show any cytotoxicity towards the normal cell lines. The results advance the position of substituted triazoles in the area of drug design with no ambiguity.

Biophysical Insight into the Interaction of Human Lysozyme with Anticancer Drug Anastrozole: A Multitechnique Approach

In the present study, we employ fluorescence spectroscopy, dynamic light scattering, and molecular docking methods. Binding of anticancer drug anastrozole with human lysozyme (HL) is studied. Binding of anastrozole to HL is moderate but spontaneous. There is anastrozole persuaded hydrodynamic change in HL, leading to molecular compaction. Binding of anastrozole to HL also decreased in vitro lytic activity of HL. Molecular docking results suggest the electrostatic interactions and van der Waals forces played key role in binding interaction of anastrozole near the catalytic site. Binding interaction of anastrozole to proteins other than major transport proteins in blood can significantly affect pharmacokinetics of this molecule. Hence, rationalizing drug dosage is important. This study also points to unrelated effects that small molecules bring in the body that are considerable and need thorough investigation.

Application of Fragment-Based Drug Discovery to Versatile Targets

Fragment-based drug discovery (FBDD) is a powerful method to develop potent small-molecule compounds starting from fragments binding weakly to targets. As FBDD exhibits several advantages over high-throughput screening campaigns, it becomes an attractive strategy in target-based drug discovery. Many potent compounds/inhibitors of diverse targets have been developed using this approach. Methods used in fragment screening and understanding fragment-binding modes are critical in FBDD. This review elucidates fragment libraries, methods utilized in fragment identification/confirmation, strategies applied in growing the identified fragments into drug-like lead compounds, and applications of FBDD to different targets. As FBDD can be readily carried out through different biophysical and computer-based methods, it will play more important roles in drug discovery.

Theoretical Investigations on Interactions of Arylsulphonyl Indazole Derivatives as Potential Ligands of VEGFR2 Kinase

Vascular endothelial growth factor receptor 2 (VEGFR2) is a key receptor in the angiogenesis process. The VEGFR2 expression is upregulated in many cancers so this receptor is an important target for anticancer agents. In the present paper, we analyse interactions of several dimeric indazoles, previously investigated for anticancer activity, with the amino acids present in the VEGFR2 binding pocket. Using the docking method and MD simulations as well as theoretical computations (SAPT0, PIEDA, semi-empirical PM7), we confirmed that these azoles can efficiently bind into the kinase pocket and their poses can be stabilised by the formation of hydrogen bonds, π–π stacking, π–cation, and hybrid interactions with some amino acids of the kinase cavity like Ala866, Lys868, Glu885, Thr916, Glu917, and Phe918.

Combining Allosteric and Orthosteric Drugs to Overcome Drug Resistance

Historically, most drugs target protein orthosteric sites. The gradual emergence of resistance hampers their therapeutic effectiveness, posing a challenge to drug development. Coadministration of allosteric and orthosteric drugs provides a revolutionary strategy to circumvent drug resistance, as drugs targeting the topologically distinct allosteric sites can restore or even enhance the efficacy of orthosteric drugs. Here, we comprehensively review the latest successful examples of such combination treatments against drug resistance, with a focus on their modes of action and the underlying structural mechanisms. Our work supplies an innovative insight into such promising methodology against the recalcitrant drug resistance conundrum and will be instructive for future clinical therapeutics.