A novel tetrazole analogue of resveratrol is a potent anticancer agent

Rescue of ApoE4-related lysosomal autophagic failure in Alzheimer's disease by targeted small molecules

Homozygosity for the ε4 allele of APOE increases the odds of developing Alzheimer's by 12 to 15 times relative to the most common ε3;ε3 genotype, and its association with higher plaque loads comports with evidence that APOEε4 compromises autophagy. The ApoE4 protein specifically binds a cis element ("CLEAR") in the promoters of several autophagy genes to block their transcription. We used a multifaceted approach to identify a druggable site in ApoE4, and virtual screening of lead-like compounds identified small molecules that specifically bind to this site to impede ApoE4::DNA binding. We validated these molecules both in vitro and in vivo with models expressing ApoE4, including ApoE4 targeted-replacement mice. One compound was able to significantly restore transcription of several autophagy genes and protected against amyloid-like aggregation in a C. elegans AD model. Together, these findings provide proof-of-principle evidence for pharmacological remediation of lysosomal autophagy by ApoE4 via ApoE4-targeted lead molecules that represent a novel tack on neurodegenerative disorders.

A Review on the Mechanism and Structure-activity Relationship of Resveratrol Heteroaryl Analogues

Resveratrol is one of the most interesting naturally-occurring nonflavonoid phenolic compounds with various biological activities, such as anticancer, neuroprotection, antibacterial, and anti-inflammatory. However, there is no clinical usage of resveratrol due to either its poor activity or poor pharmacokinetic properties. Heteroarenes-modified resveratrol is one pathway to improve its biological activities and bioavailability, and form more modification sites. In this review, we present the progress of heteroaryl analogues of resveratrol with promising biological activities in the latest five years, ranging from the synthesis to the structure-activity relationship and mechanism of actions. Finally, introducing heteroarenes into resveratrol is an effective strategy, which focuses on the selectivity of structure-activity relationship in vivo.

Novel Tetrazole Derivatives Targeting Tubulin Endowed with Antiproliferative Activity against Glioblastoma Cells

Increasing awareness of the structure of microtubules has made tubulin a relevant target for the research of novel chemotherapies. Furthermore, the particularly high sensitivity of glioblastoma multiforme (GBM) cells to microtubule disruption could open new doors in the search for new anti-GBM treatments. However, the difficulties in developing potent anti-tubulin drugs endowed with improved pharmacokinetic properties necessitates the expansion of medicinal chemistry campaigns. The application of an ensemble pharmacophore screening methodology helped to optimize this process, leading to the development of a new tetrazole-based tubulin inhibitor. Considering this scaffold, we have synthesized a new family of tetrazole derivatives that achieved remarkable antimitotic effects against a broad panel of cancer cells, especially against GBM cells, showing high selectivity in comparison with non-tumor cells. The compounds also exerted high aqueous solubility and were demonstrated to not be substrates of efflux pumps, thus overcoming the main limitations that are usually associated with tubulin binding agents. Tubulin polymerization assays, immunofluorescence experiments, and flow cytometry studies demonstrated that the compounds target tubulin and arrest cells at the G2/M phase followed by induction of apoptosis. The docking experiments agreed with the proposed interactions at the colchicine site and explained the structure-activity relationships.

In silico analysis of TUBA4A mutations in Amyotrophic Lateral Sclerosis to define mechanisms of microtubule disintegration

Amyotrophic lateral sclerosis (ALS) is an inexorably progressive and degenerative disorder of motor neurons with no currently-known cure. Studies to determine the mechanism of neurotoxicity and the impact of ALS-linked mutations (SOD1, FUS, TARDP, C9ORF72, PFN1, TUBA4A and others) have greatly expanded our knowledge of ALS disease mechanisms and have helped to identify potential targets for ALS therapy. Cellular pathologies (e.g., aggregation of mutant forms of SOD1, TDP43, FUS, Ubiqulin2, PFN1, and C9ORF72), mitochondrial dysfunction, neuroinflammation, and oxidative damage are major pathways implicated in ALS. Nevertheless, the selective vulnerability of motor neurons remains unexplained. The importance of tubulins for long-axon infrastructure, and the special morphology and function of motor neurons, underscore the central role of the cytoskeleton. The recent linkage of mutations to the tubulin α chain, TUBA4A, to familial and sporadic cases of ALS provides a new investigative opportunity to shed light on both mechanisms of ALS and the vulnerability of motor neurons. In the current study we investigate TUBA4A, a structural microtubule protein with mutations causal to familial ALS, using molecular-dynamic (MD) modeling of protein structure to predict the effects of each mutation and its overall impact on GTP binding, chain stability, tubulin assembly, and aggregation propensity. These studies predict that each of the reported mutations will cause notable structural changes to the TUBA4A (α chain) tertiary protein structure, adversely affecting its physical properties and functions. Molecular docking and MD simulations indicate certain α chain mutations (e.g. K430N, R215C, and W407X) may cause structural deviations that impair GTP binding, and plausibly prevent or destabilize tubulin polymerization. Furthermore, several mutations (including R320C and K430N) confer a significant increase in predicted aggregation propensity of TUBA4A mutants relative to wild-type. Taken together, these in silico modeling studies predict structural perturbations and disruption of GTP binding, culminating in failure to form a stable tubulin heterocomplex, which may furnish an important pathogenic mechanism to trigger motor neuron degeneration in ALS.

Synthesis, biological evaluation, and structure-activity relationships of new tubulin polymerization inhibitors based on 5-amino-1,2,4-triazole scaffold

Based on our previous research, thirty new 5-amino-1H-1,2,4-triazoles possessing 3,4,5-trimethoxyphenyl moiety were synthesized, and evaluated for antiproliferative activities. Among them, compounds IIa, IIIh, and IIIm demonstrated significant antiproliferative activities against a panel of tumor cell lines, and the promising compound IIIm dose-dependently caused G2/M phase arrest in HeLa cells. Furthermore, analogue IIa exhibited the most potent tubulinpolymerization inhibitory activity with an IC₅₀ value of 9.4 μM, and molecular modeling studies revealed that IIa formed stable interactions in the colchicine-binding site of tubulin, suggesting that 5-amino-1H-1,2,4-triazole scaffold has potential for further investigation to develop novel tubulin polymerization inhibitors with anticancer activity.

Resveratrol and other Stilbenes: Effects on Dysregulated Gene Expression in Cancers and Novel Delivery Systems

Trans-resveratrol (RESV), pterostilbene, trans-piceid and trans-viniferins are bioactive stilbenes present in grapes and other plants. Several groups applied biotechnology to introduce their synthesis in plant crops. Biochemical interaction with enzymes, regulation of non-coding RNAs, and activation of signaling pathways and transcription factors are among the main effects described in literature. However, solubility in ethanol, short half-life, metabolism by gut bacteria, make the concentration responsible for the effects observed in cultured cells difficult to achieve. Derivatives obtained by synthesis, trans-resveratrol analogs and methoxylated stilbenes show to be more stable and allow the synthesis of bioactive compounds with higher bioavailability. However, changes in chemical structure may require testing for toxicity. Thus, the delivery of RESV and its natural analogs incorporated into liposomes or nanoparticles, is the best choice to ensure stability during administration and appropriate absorption. The application of RESV and its derivatives with anti-inflammatory and anticancer activity is presented with description of novel clinical trials.

Ultrasound assisted synthesis of tetrazole based pyrazolines and isoxazolines as potent anticancer agents via inhibition of tubulin polymerization

In search of new active molecules against MCF-7, A549 and HepG2, tetrazole based pyrazoline and isoxazoline derivatives under both conventional and ultrasonic irradiation method were designed and efficiently synthesized. Structures of newly synthesized compounds 5a-h and 6a-h were characterized by ¹H NMR, ¹³C NMR, MS and elemental analysis. Several derivatives were found to be excellent cytotoxic against MCF-7, A549 and HepG2 cell lines characterized by lower IC₅₀ values (0.78-3.12 µg/mL). Compounds 5b and 5c demonstrated an antiproliferative effect comparable to that of CA-4. Western blot analysis revealed that, reported compounds accumulate more tubulin in the soluble fraction. Docking studies suggested that, binding of these compounds mimics at the colchicine site of tubulin. In vitro study revealed that the tetrazole based pyrazolines and isoxazolines may possess ideal structural requirements for further development of novel therapeutic agents.

Structural modeling of GSK3β implicates the inactive (DFG-out) conformation as the target bound by TDZD analogs

Glycogen synthase kinase-3β (GSK3β) controls many physiological pathways, and is implicated in many diseases including Alzheimer’s and several cancers. GSK3β-mediated phosphorylation of target residues in microtubule-associated protein tau (MAPTAU) contributes to MAPTAU hyperphosphorylation and subsequent formation of neurofibrillary tangles. Inhibitors of GSK3β protect against Alzheimer’s disease and are therapeutic for several cancers. A thiadiazolidinone drug, TDZD-8, is a non-ATP-competitive inhibitor targeting GSK3β with demonstrated efficacy against multiple diseases. However, no experimental data or models define the binding mode of TDZD-8 with GSK3β, which chiefly reflects our lack of an established inactive conformation for this protein. Here, we used metadynamic simulation to predict the three-dimensional structure of the inactive conformation of GSK3β. Our model predicts that phosphorylation of GSK3β Serine9 would hasten the DFG-flip to an inactive state. Molecular docking and simulation predict the TDZD-8 binding conformation of GSK3β to be inactive, and are consistent with biochemical evidence for the TDZD-8–interacting residues of GSK3β. We also identified the pharmacophore and assessed binding efficacy of second-generation TDZD analogs (TDZD-10 and Tideglusib) that bind GSK3β as non-ATP-competitive inhibitors. Based on these results, the predicted inactive conformation of GSK3β can facilitate the identification of novel GSK3β inhibitors of high potency and specificity.

Tetrazoles as anticancer agents: A review on synthetic strategies, mechanism of action and SAR studies

Cancer is a leading cause of death worldwide. Even after the availability of numerous drugs and treatments in the market, scientists and researchers are focusing on new therapies because of their resistance and toxicity issues. The newly synthesized drug candidates are able to demonstrate in vitro activity but are unable to reach clinical trials due to their rapid metabolism and low bioavailability. Therefore there is an imperative requisite to expand novel anticancer negotiators with tremendous activity as well as in vivo efficacy. Tetrazole is a promising pharmacophore which is metabolically more stable and acts as a bioisosteric analogue for many functional groups. Tetrazole fragment is often castoff with other pharmacophores in the expansion of novel anticancer drugs. This is the first systematic review that emphasizes on contemporary strategies used for the inclusion of tetrazole moiety, mechanistic targets along with comprehensive structural activity relationship studies to provide perspective into the rational design of high-efficiency tetrazole-based anticancer drug candidates.

Resveratrol - A comprehensive review of recent advances in anticancer drug design and development

Resveratrol is a natural polyphenolic stilbene isolated from various plants, foods and beverages with a broad spectrum of biological and pharmacological properties through modulating diverse targets and signaling pathways. Particularly, it has attracted a great deal of attention as a promising and multitarget anticancer agent due to its potential use in chemoprevention and chemotherapy of various tumors. However, unfavorable pharmacokinetics/pharmacodynamics profile such as poor bioavailability restricted its applications. Therefore, medicinal chemists have synthesized a lot of novel derivatives and analogues of resveratrol using different modification strategies to overcome these limitations and improve anticancer efficacy. Herein, we reviewed the design, synthesis, structure-activity relationship and mechanism of the most potent and privileged resveratrol-based compounds that showed promising anticancer activities in the last five years. We classified these compounds into the ten different categories based on their chemical structure similarities.

Computational target-based drug repurposing of elbasvir, an antiviral drug predicted to bind multiple SARS-CoV-2 proteins

Coronavirus disease 19 (COVID-19) is a severe acute respiratory syndrome caused by SARS-CoV-2 (2019-nCoV). While no drugs have yet been approved to treat this disease, small molecules effective against other viral infections are under clinical evaluation for therapeutic abatement of SARS-CoV-2 infections. Ongoing clinical trials include Kaletra (a combination of two protease inhibitors approved for HIV treatment), remdesivir (an investigational drug targeting RNA-dependent RNA polymerase [RdRP] of SARS-CoV-2), and hydroxychloroquine (an approved anti-malarial and immuno-modulatory drug). Since SARS-CoV-2 replication depends on three virally encoded proteins (RdRP, papain-like proteinase, and helicase), we screened 54 FDA-approved antiviral drugs and ~3300 investigational drugs for binding to these proteins using targeted and unbiased docking simulations and computational modeling. Elbasvir, a drug approved for treating hepatitis C, is predicted to bind stably and preferentially to all three proteins. At the therapeutic dosage, elbasvir has low toxicity (liver enzymes transiently elevated in 1% of subjects) and well-characterized drug-drug interactions. We predict that treatment with elbasvir, alone or in combination with other drugs such as grazoprevir, could efficiently block SARS-CoV-2 replication. The concerted action of elbasvir on at least three targets essential for viral replication renders viral mutation to drug resistance extremely unlikely.

Molecular design, synthesis and biological characterization of novel Resveratrol derivative as potential anticancer agent targeting NF-κB

Resveratrol (RESV), an anticancer nutraceutical compound, is known to show poor bioavailability inside the human body. Therefore, this study has designed multiple chemical analogs of RESV compound for improving its pharmacokinetic as well as its anti-cancer properties. Initially, the drug likeliness and ADME-toxicity properties of these new chemical analogs were tested with the help of diverse computational approaches. Then the best predicted RESV derivative is synthesized by the organic method, and its NF-κB mediated anti-tumor activity assessed on histiocytic lymphoma U-937 cells. The new synthetic RESV analog, i.e. (E)-3-(prop-2-yn-1-yloxy)-5-(4-(prop-2-yn-1-yloxy) styryl) phenol has shown a rapid, persistent and better dose-dependent (IC50 of 7.25 μM) decrease in the viability of U937 cells than the native (IC50 of 30 μM) RESV compound. This analog has also demonstrated its potential ability in inducing apoptosis through DNA ladder formation. At 10 µg/ml concentration, this chemical derivative has shown a better NF-κB inhibition (IC50 is 2.45) compared to the native RESV compound (IC50 is 1.95). Molecular docking analysis found that this analog exerts its anti- NF-κB activity (binding energy of -6.78 kcal/mol and Ki 10 µM) by interacting with DNA binding residues (Arg246, Lys444, and Gln606) of p50 chain NF-κB. This study presents a novel RESV analog that could further develop as a potential anti-NF-κB mediated tumor inhibitor.

Tetrazole hybrids with potential anticancer activity

Cancer is one of the main causes of death throughout the world. The anticancer agents are indispensable for the treatment of various cancers, but most of them currently on the market are not specific, resulting in series of side effects of chemotherapy. Moreover, the emergency of drug-resistance towards cancers has already increased up to alarming level in the recent decades. Therefore, it's imperative to develop novel anticancer candidates with excellent activity against both drug-susceptible and drug-resistant cancers, and low toxicity as well. Tetrazole is the bioisoster of carboxylic acid, and its derivatives demonstrated promising anticancer activity. Hybridization of tetrazole with other anticancer pharmacophores may provide novel candidates with anticancer potency. The present review described the anticancer activity of tetrazole hybrids, and the structure-activity relationship (SAR) is also discussed to provide an insight for rational designs of tetrazole anticancer candidates with higher efficiency.

Synthesis and Evaluation of Antidepressant Activities of 5-Aryl-4,5-dihydrotetrazolo [1,5-a]thieno[2,3-e]pyridine Derivatives

In this study, we synthetized a series of 5-aryl-4,5-dihydrotetrazolo[1,5-a]thieno[2,3-e]pyridine derivatives containing tetrazole and other heterocycle substituents, i.e., triazole, methyltriazole, and triazolone. The forced swim test (FST) and tail suspension test (TST) were used to evaluate the antidepressant activity of the target compounds. The compound 5-[4-(trifluoromethyl)phenyl]-4,5-dihydrotetrazolo[1,5-a]thieno[2,3-e]pyridine (4i) showed the highest antidepressant activity, with a reduced immobility time of 55.33% when compared with the control group. Using an open-field test, compound 4i was shown to not affect spontaneous activity of mice. The determination of in vivo 5-hydroxytryptamine (5-HT) concentration showed that compound 4i may have an effect in the mouse brain. The biological activities of all synthetized compounds were verified by molecular docking studies. Compound 4i showed significant interactions with residues of the 5-HT1A receptor homology model.