Discovery of new quinolines as potent colchicine binding site inhibitors: design, synthesis, docking studies, and anti-proliferative evaluation

Investigating the Antiproliferative Activity of Novel 4-Chloro-8-Nitro-1,2-Dihydro-3-Quinoline Acylhydrazones on Human Cervical Cancer Cell Lines

A new series of acyl hydrazones have been synthesized from 4-chloro-8-nitro-1,2-dihydroquinoline-3-carbaldehyde. These compounds were characterized using various spectroscopic techniques. Density functional theoretical (DFT) studies were conducted to understand the correlation between electronic parameters and biological activity. The biological activity of the compounds was theoretically examined through molecular docking and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) analysis. The compounds demonstrated high absorption rates and were found to be non-hepatotoxic. Preliminary cytotoxicity screenings against HeLa cell lines identified compound 7 as the most potent, with an IC50 value of 18.8 μM. This compound was further selected for bioimaging studies. The results indicate that compound 7 induces apoptosis at its IC50 concentration, suggesting its potential as an anticancer agent.

Design and synthesis of novel multi-target tetrabromophthalimides as CBS and Topo-II inhibitors and DNA intercalators

Microtubules are highly dynamic structures and constitute a crucial component of the cellular cytoskeleton. Besides, topoisomerases (Topo) play a fundamental role in maintaining the appropriate structure and organization of DNA. On the other hand, dual mechanism drug candidates for cancer treatment primarily aim to enhance the efficacy of cancer treatment and potentially overcome drug resistance. Hence, this work was tailored to design and synthesize new multi-target tetrabromophthalimide derivatives (2a-2k) that are capable of inhibiting the colchicine binding site (CBS) and topoisomerase II (Topo-II). The conducted in vitro studies showed that compound 2f showed the lowest IC50 value (6.7 μg mL-1) against the MDA-MB-468 cancer cell line. Additionally, compound 2f prompted upregulation of pro-apoptotic markers (caspases 3, 7, 8, and 9, Bax and p53). Moreover, some anti-apoptotic proteins (MMP2, MMP9, and BCL-2) were downregulated by compound 2f treatment. Besides, the colchicine binding assay showed that compounds 2f and 2k displayed promising inhibitory potential with IC50 values of 1.92 and 4.84 μg mL-1, respectively, in comparison with colchicine (1.55 μg mL-1). Furthermore, the Topo-II inhibition assay displayed the prominent inhibitory potential of compound 2f with an IC50 value of 15.75 μg mL-1, surpassing the IC50 of etoposide (20.82 μg mL-1). Cell cycle analysis revealed that compound 2f induced cell cycle arrest at both the G0-G1 and G2-M phases. The new candidates were docked against both the CBS (PDB ID: 5XIW) and Topo-II (PDB ID: 5CDP) targets to investigate their binding interactions and affinities as well. Accordingly, the synthesized compounds could serve as promising multi-target anticancer candidates with eligible apoptotic activity.

Novel Antimitotic Agent SP-1-39 Inhibits Head and Neck Squamous Cell Carcinoma

Effective management of head and neck cancer (HNC) poses a significant challenge in the field of oncology, due to its intricate pathophysiology and limited treatment options. The most common HNC malignancy is head and neck squamous cell carcinoma (HNSCC). HNSCC treatment includes a combination of surgery, radiation, and chemotherapy. While HNSCC is treatable if diagnosed early, this is often not the case and is considered incurable once in its late stages and metastatic disease has developed. Therapies are also limited once resistant disease has occurred. SP-1-39, a novel colchicine-binding site inhibitor (CBSI), has been recently reported for its potential efficacy in a variety of cancer cell lines including breast, melanoma, pancreatic, and prostate. SP-1-39 also shows abilities to overcome paclitaxel resistance in a paclitaxel-resistant prostate cancer xenograft model. To evaluate the potential of SP-1-39 as a new HNSCC treatment option, herein we systematically performed preclinical studies in HNSCC models using SP-1-39 and demonstrated that, in vitro, SP-1-39 inhibits the proliferation of 2 HNSCC cell lines with low nanomolar IC50 values (1.4 to 2.1 nM), induces HNSCC cell apoptosis in a dose-dependent manner, interferes with migration of HNSCC cells, and leads to HNSCC cell cycle arrest in the G2/M phase. In vivo, SP-1-39 suppresses the primary tumor growth of a Detroit 562 subcutaneous xenograft mouse model in 6- to 8-wk-old, male NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ) mice, with no detectable cytotoxic effects at a low dose of 2.5 mg/kg. This efficacy of SP-1-39 is better when compared with the treatment using a reference chemotherapy drug, paclitaxel at 10 mg/kg. Collectively, these data demonstrate that SP-1-39 is a promising candidate for further development for more efficacious HNSCC treatment.

Exploring the antitumor potential of novel quinoline derivatives via tubulin polymerization inhibition in breast cancer; design, synthesis and molecular docking

A series of quinoline derivatives was designed and synthesized as novel tubulin inhibitors targeting the colchicine binding site. All the rationalized compounds 3a-e, 4a-e, 5a-e, and 6a-e have been chosen for screening their cytotoxic activity against 60 cell lines by NCI. Compounds 3b, 3c, 4c, 5c and 6c demonstrated the most notable antitumor activity against almost all cell lines. Compound 4c emerged as the most potent compound as an antiproliferative agent. This compound was subsequently chosen for five-dose testing and it exhibited remarkable broad-spectrum efficacy with strong antitumor activity against several cell lines. Compound 4c significantly induced cell cycle arrest in MDA-MB-231 cells at G2 and M phases where the cell population increased dramatically to 22.84% compared to the untreated cells at 10.42%. It also increased the population in MDA-MB-231 cells at both early and late stages of apoptosis. Compound 4c can successfully inhibit tubulin polymerization with an IC50 value of 17 ± 0.3 μM. The β-tubulin mRNA levels were notably reduced in MDA-MB-231 cells treated with compound 4c which is similar to the effect observed with colchicine treatment. Docking studies revealed that compound 4c interacted well with crucial amino acids in the active site.

Design and synthesis of novel tetrabromophthalimide derivatives as potential tubulin inhibitors endowed with apoptotic induction for cancer treatment

Although various approaches exist for treating cancer, chemotherapy continues to hold a prominent role in the management of this disease. Besides, microtubules serve as a vital component of the cellular skeleton, playing a pivotal role in the process of cell division making it an attractive target for cancer treatment. Hence, the scope of this work was adapted to design and synthesize new anti-tubulin tetrabromophthalimide hybrids (3-17) with colchicine binding site (CBS) inhibitory potential. The conducted in vitro studies showed that compound 16 displayed the lowest IC50 values (11.46 µM) at the FaDu cancer cell lines, whereas compound 17 exhibited the lowest IC50 value (13.62 µM) at the PC3 cancer cell line. However, compound 7b exhibited the lowest IC50 value (11.45 µM) at the MDA-MB-468 cancer cell line. Moreover, compound 17 was observed to be the superior antitumor candidate against all three tested cancer cell lines (MDA-MB-468, PC3, and FaDu) with IC50 values of 17.22, 13.15, and 13.62 µM, respectively. In addition, compound 17 showed a well-established upregulation of apoptotic markers (Caspases 3, 7, 8, and 9, Bax, and P53). Moreover, compound 17 induced downregulation of the antiapoptotic markers (MMP2, MMP9, and BCL-2). Furthermore, the colchicine binding site inhibition assay showed that compounds 15a and 17 exhibited particularly significant inhibitory potentials, with IC50 values of 23.07 and 4.25 µM, respectively, compared to colchicine, which had an IC50 value of 3.89 µM. Additionally, cell cycle analysis was conducted, showing that compound 17 could prompt cell cycle arrest at both the G0-G1 and G2-M phases. On the other hand, a molecular docking approach was applied to investigate the binding interactions of the examined candidates compared to colchicine towards CBS of the β-tubulin subunit. Thus, the synthesized tetrabromophthalimide hybrids can be regarded as outstanding anticancer candidates with significant apoptotic activity.

3D-QSAR, molecular docking, simulation dynamic and ADMET studies on new quinolines derivatives against colorectal carcinoma activity

Cancer is the uncontrolled spread of abnormal cells that results in abnormal tissue growth in the affected organ. One of the most important organs is exposed to the growth of colon cancer cells, which start in the large intestine (colon) or the rectum. Several therapeutic protocols were used to treat different kinds of cancer. Recently, several studies have targeted tubulin and microtubules due to their remarkable prefoliation. Also, recent research shows that quinoline compounds have significant efficacy against human colorectal cancer. So, the present work investigated the potential of thirty quinoline compounds as tubulin inhibitors using computational methods. A 3D-QSAR approach using two contours (CoMFA and CoMSIA), molecular docking simulation to determine the binding type of the complexes (ligand-receptor), molecular dynamics simulation and identifying pharmacokinetic characteristics were used to design molecules. For all compounds designed (T1-5), molecular docking was used to compare the stability by type of binding. The ADMET has been utilized for molecules with good stability in molecular docking (T1-3); these compounds have good medicinal characteristics. Furthermore, a molecular dynamics simulation (MD) at 100 ns was performed to confirm the stability of the T1-3 compounds; the molecules (T1-3) remained the most stable throughout the simulation. The compounds T1, T2 and T3 are the best-designed drugs for colorectal carcinoma treatments.Communicated by Ramaswamy H. Sarma.

An update on the development on tubulin inhibitors for the treatment of solid tumors

INTRODUCTION

Microtubules play a vital role in cancer therapeutics. They are implicated in tumorigenesis, thus inhibiting tubulin polymerization in cancer cells, and have now become a significant target for anticancer drug development. A plethora of drug molecules has been crafted to influence microtubule dynamics and presently, numerous tubulin inhibitors are being investigated. This review discusses the recently developed inhibitors including natural products, and also examines the preclinical and clinical data of some potential molecules.

AREA COVERED

The current review article summarizes the development of tubulin inhibitors while detailing their specific binding sites. It also discusses the newly designed inhibitors that may be useful in the treatment of solid tumors.

EXPERT OPINION

Microtubules play a crucial role in cellular processes, especially in cancer therapy where inhibiting tubulin polymerization holds promise. Ongoing trials signify a commitment to revolutionizing cancer treatment and exploring targeted therapies. Challenges in microtubule modulation, like resistance and off-target effects, demand focused efforts, emphasizing combination therapies and personalized treatments. Beyond microtubules, promising avenues in cancer research include immunotherapy, genomic medicine, CRISPR gene editing, liquid biopsies, AI diagnostics, and stem cell therapy, showcasing a holistic approach for future advancements.

Anti-rheumatic colchicine phytochemical exhibits potent antiviral activities against avian and seasonal Influenza A viruses (IAVs) via targeting different stages of IAV replication cycle

BACKGROUND

The continuous evolution of drug-resistant influenza viruses highlights the necessity for repurposing naturally-derived and safe phytochemicals with anti-influenza activity as novel broad-spectrum anti-influenza medications.

METHODS

In this study, nitrogenous alkaloids were tested for their viral inhibitory activity against influenza A/H1N1 and A/H5N1 viruses. The cytotoxicity of tested alkaloids on MDCK showed a high safety range (CC50 > 200 µg/ml), permitting the screening for their anti-influenza potential.

RESULTS

Herein, atropine sulphate, pilocarpine hydrochloride and colchicine displayed anti-H5N1 activities with IC50 values of 2.300, 0.210 and 0.111 µg/ml, respectively. Validation of the IC50 values was further depicted by testing the three highly effective alkaloids, based on their potent IC50 values against seasonal influenza A/H1N1 virus, showing comparable IC50 values of 0.204, 0.637 and 0.326 µg/ml, respectively. Further investigation suggests that colchicine could suppress viral infection by primarily interfering with IAV replication and inhibiting viral adsorption, while atropine sulphate and pilocarpine hydrochloride could directly affect the virus in a cell-free virucidal effect. Interestingly, the in silico molecular docking studies suggest the abilities of atropine, pilocarpine, and colchicine to bind correctly inside the active sites of the neuraminidases of both influenza A/H1N1 and A/H5N1 viruses. The three alkaloids exhibited good binding energies as well as excellent binding modes that were similar to the co-crystallized ligands. On the other hand, consistent with in vitro results, only colchicine could bind correctly against the M2-proton channel of influenza A viruses (IAVs). This might explicate the in vitro antiviral activity of colchicine at the replication stage of the virus replication cycle.

CONCLUSION

This study highlighted the anti-influenza efficacy of biologically active alkaloids including colchicine. Therefore, these alkaloids should be further characterized in vivo (preclinical and clinical studies) to be developed as anti-IAV agents.

Nitrogen-fused Heterocycles: Empowering Anticancer Drug Discovery

The worldwide impact of cancer is further compounded by the constraints of current anticancer medications, which frequently exhibit a lack of selectivity, raise safety apprehensions, result in significant adverse reactions, and encounter resistance mechanisms. The current situation highlights the pressing need to develop novel and more precise anticancer agents that prioritize safety and target specificity. Remarkably, more than 85% of drugs with physiological activity contain heterocyclic structures or at least one heteroatom. Nitrogen-containing heterocycles hold a significant position among these compounds, emerging as the most prevalent framework within the realm of heterocyclic chemistry. This article explores the medicinal chemistry behind these molecules, highlighting their potential as game-changing possibilities for anticancer medication development. The analysis highlights the inherent structural variety in nitrogen-containing heterocycles, revealing their potential to be customized for creating personalized anticancer medications. It also emphasizes the importance of computational techniques and studies on the relationships between structure and activity, providing a road map for rational medication design and optimization. Nitrogen- containing heterocycles are a promising new area of study in the fight against cancer, and this review summarises the state of the field so far. By utilizing their inherent characteristics and exploiting cooperative scientific investigations, these heterocyclic substances exhibit potential at the forefront of pioneering therapeutic approaches in combating the multifaceted obstacles posed by cancer.

Heteroaromatization of Coumarin Part I: Design, Synthesis, Reactions, Antitumor Activities of Novel Pyridine and Naphthyridine Derivatives

INTRODUCTION

A novel series of chromen-3-yl-pyridine moieties were synthesized. IR, NMR, and MS spectroscopy were used to confirm the structure of these novel compounds and study antitumor activity of these compounds. The structure-activity relationship investigation demonstrated that 2,4-diamino- 5-(3-methoxyphenyl)-7-(2-oxo-2H-chromen-3-yl)-1,8-naphthyridine-3-carbonitrile (16), naphthyridine- 3-carbonitrile derivatives 17, 18 and pyrido[2,3-d]pyrimidine derivative 12 were found to be more effective, while compounds 5a,b, 9c, 11, 13 and 14 showed moderate activity for antitumor activities.

OBJECTIVES

The objective was to design a series of new chromen-3-yl-pyridine and pyrido[2,3-d]pyrimidine derivatives and study the antitumor of these compounds.

MATERIALS AND METHODS

The condensation reaction of 3-acetyl-2H-chromen-2-one with 3-methoxy benzaldehyde and malononitrile or ethyl cyanoacetate in the presence of ammonium acetate and acetic acid under reflux to give the corresponding chromen-3-yl pyridine-3-carbonitrile derivatives.

RESULTS

In this study, the antitumor activity of the synthesized compounds chromen-3-yl-pyridine derivatives has been determined for the broad spectrum of cytotoxic activity toward the investigated three cell lines and 5-Fluorouracil, as reference drugs.

CONCLUSION

A series of new chromen-3-yl-pyridine and pyrido[2,3-d]pyrimidine derivatives were synthesized in this work. All compounds were evaluated for cytotoxic activity.

Optimization of oil yield of Pelargonium graveolens L'Hér using Box-Behnken design in relation to its antimicrobial activity and in silico study

Pelargonium graveolens L'Hér is an important species of genus Pelargonium with an economic value. The unique rose scent of its oil is used in perfume and cosmetic industry. The oil is characterized by the presence of citronellol, geraniol and rose oxide. Fresh aerial parts of P. graveolens at GC-MS analysis of four seasons revealed that autumn constituted the highest yield of the oil. For the first time, optimization of the yield of extracted oil of P. graveolens was performed employing 3-level Box-Behnken design using 3-factors. The GC-MS analysis of the essential oil was performed for the 17-runs. The optimized extraction of the oil was performed employing numerical optimization and studied for antimicrobial, Minimum Inhibitory Concentration (MIC) and biofilm inhibitory activities. The 3 factors followed rank (plant material amount > water volume > NaCl percent in water), in their magnitude of effect on increasing yield of the oil. Increasing the plant material amount increased the yield of the oil by 6-folds compared to NaCl percent in water. The optimized yield of oil (4 ml) was obtained from extraction criteria (150 g of plant, 750 ml of water and 3.585% (26.85 g) of NaCl). Computational docking was performed to overcome the multi-drug resistant Gram-negative bacilli targeting undecaprenyl pyrophosphate synthase (UPPS). The optimized oil exhibited a promising inhibitory activity against Gram-negative bacteria (K. pneumonia and P. aeruginosa) with significant antibiofilm action (P < 0.05). Moreover, it exerted a synergistic effect when combined with various antibiotics (Cefoxitin, Cloxacillin, Oxacillin and Vancomycin) against MRSA clinical strains.

Organotin Benzohydroxamate Derivatives (OTBH) Target Colchicine-binding Site Exerting Potent Antitumor Activity both in Vitro and Vivo Revealed by Quantitative Proteomic Analysis

The activity of four typical organotin benzohydroxamate compounds (OTBH) with the different electronegativity of fluorine and chlorine atoms was assessed both in vitro and in vivo, revealing that they all exhibited notable antitumor effects. Furthermore, it was discovered that the biochemical capacity against cancer was influenced by their substituents' electronegativity and structural symmetry. For instance, benzohydroxamate derivatives with single chlorine at the fourth site on the benzene ring, two normal-butyl organic ligands, a symmetrical structure, and so on ([n-Bu₂Sn[{4-ClC₆H₄C(O)NHO}₂] (OTBH-1)) had stronger antitumor activity than others. Furthermore, the quantitative proteomic analysis discovered 203 proteins in HepG2 cells and 146 proteins in rat liver tissues that were differently identified before and after administration. Simultaneously, bioinformatics analysis of differentially expressed proteins demonstrated that the antiproliferative effects involved in the microtubule-based process, tight junction and its downstream apoptosis pathways. As predicted analytically, molecular docking indicated that ''-O-'' were the target docking atoms for the colchicine-binding site; meanwhile, this site was additionally verified by the EBI competition experiment and the microtubule assembly inhibition test. In conclusion, these derivatives promising for developing microtubule-targeting agents (MTAs) were shown to target the colchicine-binding site, impair cancer cell microtubule networks, and then halt mitosis and trigger apoptosis.

Design, synthesis, molecular dynamics simulation, MM/GBSA studies and kinesin spindle protein inhibitory evaluation of some 4-aminoquinoline hybrids

The discovery of novel chemotherapeutic agents is always challenging for researchers in industry and academia. Among the recent promising anticancer therapeutic targets, an important modulatory factor in mitosis is the expression of the kinesin family motor protein (Eg5). In terms of chemotherapy treatment, mitosis has gained significant attention due to its role as one of the biological processes that can be intervened in it. This study was undertaken to design, synthesise and evaluation of 4-aminoquinoline hybrid compounds as potential Eg5 inhibitors. Based on data collected from Malachite green and steady state ATPase assays, it has been determined that compounds such as 6c, 6d, 6g, and 6h are sensitive to Eg5 inhibition. In special mention, compounds 4 and 6c showed promising inhibitory activity in Malachite green assay with IC₅₀ values of 2.32 ± 0.23 µM and 1.97 ± 0.23 µM respectively. Compound 4 showed favourable inhibitory potential Steady state ATPase Assay with IC₅₀ value of 5.39 ± 1.39 µM. We performed molecular docking, MM/GBSA calculations, and molecular dynamic simulations to evaluate the interactions between ligands and the binding site of the kinesin spindle protein to evaluate the functional consequences of these interactions. As a result of these findings, it can be concluded that these 4-amioquinoline Schiff's base hybrids may prove to be promising candidates for development as novel inhibitors of Eg5. Further in-vivo research in this area is required.

Discovery of a novel Coumarin-Dihydroquinoxalone derivative MY-673 as a tubulin polymerization inhibitor capable of inhibiting the ERK pathway with potent anti-gastric cancer activities

As a class of microtubule targeting agents, colchicine binding site inhibitors (CBSIs) are considered as promising drug candidates for cancer therapy. However, due to adverse reactions, there are currently no CBSIs approved by FDA for cancer treatment. Therefore, extensive efforts are still encouraged to find novel CBSIs with different chemical structures and better anticancer efficacies. In this work, we designed and synthesized a new coumarin-dihydroquinoxalone derivative, MY-673, and evaluated its anticancer potency in vitro and in vivo. We confirmed that MY-673 was a potent CBSI that it not only inhibited tubulin polymerization, but also exhibited significant inhibitory potency on the growth of 13 cancer cells with IC₅₀ values from 11.7 nM to 395.9 nM. Based on the results of kinase panel screening, MY-673 could inhibit ERK (extracellular regulated protein kinases) pathways-related kinases. We further confirmed that MY-673 could inhibit ERK signaling pathway in MGC-803 and HGC-27 cells, and then affected the expression level of SMAD4 protein in TGF-β (transforming growth factor β) /SMAD (small mother against decapentaplegic) signaling pathway using the western blotting assay. In addition, compound MY-673 could effectively inhibit cell proliferation, migration and induce cell apoptosis. We also further confirmed the in vivo efficacy of MY-673 in inhibiting tumor growth using the MGC-803 xenograft tumor model. At 20 mg/kg, the TGI rate was 85.9%, and it did not cause obvious toxicity to the main organs of mice. Together, the results we report here indicated that MY-673 was a promising CBSI for cancer treatment, which was capable of inhibiting the ERK pathway with potent antiproliferative activities in vitro and in vivo.

1-Benzyl-5-bromo-3-hydrazonoindolin-2-ones as Novel Anticancer Agents: Synthesis, Biological Evaluation and Molecular Modeling Insights

Human health is experiencing several obstacles in the modern medical era, particularly cancer. As a result, the cancer therapeutic arsenal should be continually expanded with innovative small molecules that preferentially target tumour cells. In this study, we describe the development of two small molecule series (7a–d and 12a–e) based on the 1-benzyl-5-bromoindolin-2-one scaffold that connected through a hydrazone linker to a 4-arylthiazole (7a–d) or 4-methyl-5-(aryldiazenyl)thiazole (12a–e) moiety. The anticancer activity of all the reported indolin-2-one derivatives was assessed against breast (MCF-7) and lung (A-549) cancer cell lines. The 4-arylthiazole-bearing derivatives 7c and 7d revealed the best anticancer activity toward MCF-7 cells (IC50 = 7.17 ± 0.94 and 2.93 ± 0.47, respectively). Furthermore, the VEGFR-2 inhibitory activity for 7c and 7d was evaluated. Both molecules disclosed good inhibitory activity, and their IC50 values were equal to 0.728 µM and 0.503 µM, respectively. Additionally, the impacts of 7d on the cell cycle phases as well as on the levels of different apoptotic markers (caspase-3, caspase-9, Bax, and Bcl-2) were assessed. Molecular docking and dynamic simulations are carried out to explore the binding mode of 7d within the VEGFR-2 active site.

Nitrogen Containing Heterocycles as Anticancer Agents: A Medicinal Chemistry Perspective

Cancer is one of the major healthcare challenges across the globe. Several anticancer drugs are available on the market but they either lack specificity or have poor safety, severe side effects, and suffer from resistance. So, there is a dire need to develop safer and target-specific anticancer drugs. More than 85% of all physiologically active pharmaceuticals are heterocycles or contain at least one heteroatom. Nitrogen heterocycles constituting the most common heterocyclic framework. In this study, we have compiled the FDA approved heterocyclic drugs with nitrogen atoms and their pharmacological properties. Moreover, we have reported nitrogen containing heterocycles, including pyrimidine, quinolone, carbazole, pyridine, imidazole, benzimidazole, triazole, β-lactam, indole, pyrazole, quinazoline, quinoxaline, isatin, pyrrolo-benzodiazepines, and pyrido[2,3-d]pyrimidines, which are used in the treatment of different types of cancer, concurrently covering the biochemical mechanisms of action and cellular targets.

Phytoestrogen β-Sitosterol Exhibits Potent In Vitro Antiviral Activity against Influenza A Viruses

Influenza is a contagious infection in humans that is caused frequently by low pathogenic seasonal influenza viruses and occasionally by pathogenic avian influenza viruses (AIV) of H5, H7, and H9 subtypes. Recently, the clinical sector in poultry and humans has been confronted with many challenges, including the limited number of antiviral drugs and the rapid evolution of drug-resistant variants. Herein, the anti-influenza activities of various plant-derived phytochemicals were investigated against highly pathogenic avian influenza A/H5N1 virus (HPAIV H5N1) and seasonal low pathogenic human influenza A/H1N1 virus (LPHIV H1N1). Out of the 22 tested phytochemicals, the steroid compounds β-sitosterol and β-sitosterol-O-glucoside have very potent activity against the predefined influenza A viruses (IAV). Both steroids could induce such activity by affecting multiple stages during IAV replication cycles, including viral adsorption and replication with a major and significant impact on the virus directly in a cell-free status "viricidal effect". On a molecular level, several molecular docking studies suggested that β-sitosterol and β-sitosterol-O-glucoside exhibited viricidal effects through blocking active binding sites of the hemagglutinin surface protein, as well as showing inhibitory effects against replication through the binding with influenza neuraminidase activity and blocking the active sites of the M2 proton channel activity. The phytoestrogen β-sitosterol has structural similarity with the active form of the female sex hormone estradiol, and this similarity is likely one of the molecular determinants that enables the phytoestrogen β-sitosterol and its derivative to control IAV infection in vitro. This promising anti-influenza activity of β-sitosterol and its O-glycoside derivative, according to both in vitro and cheminformatics studies, recommend both phytochemicals for further studies going through preclinical and clinical phases as efficient anti-influenza drug candidates.

Consensus Virtual Screening Protocol Towards the Identification of Small Molecules Interacting with the Colchicine Binding Site of the Tubulin-microtubule System

Modification of the tubulin-microtubule (Tub-Mts) system has generated effective strategies for developing different treatments for cancer. A huge amount of clinical data about inhibitors of the tubulin-microtubule system have supported and validated the studies on this pharmacological target. However, many tubulin-microtubule inhibitors have been developed from representative and common scaffolds that cover a small region of the chemical space with limited structural innovation. The main goal of this study is to develop the first consensus virtual screening protocol for natural products (ligand- and structure-based drug design methods) tuned for the identification of new potential inhibitors of the Tub-Mts system. A combined strategy that involves molecular similarity, molecular docking, pharmacophore modeling, and in silico ADMET prediction has been employed to prioritize the selections of potential inhibitors of the Tub-Mts system. Five compounds were selected and further studied using molecular dynamics and binding energy predictions to characterize their possible binding mechanisms. Their structures correspond to 5-[2-(4-hydroxy-3-methoxyphenyl) ethyl]-2,3-dimethoxyphenol (1), 9,10-dihydro-3,4-dimethoxy-2,7-phenanthrenediol (2), 2-(3,4-dimethoxyphenyl)-5,7-dihydroxy-6-methoxy-4H-1-benzopyran-4-one (3), 13,14-epoxyparvifoline-4',5',6'-trimethoxybenzoate (4), and phenylmethyl 6-hydroxy-2,3-dimethoxybenzoate (5). Compounds 1-3 have been associated with literature reports that confirm their activity against several cancer cell lines, thus supporting the utility of this protocol.

Research progress on antitumor activity of XRP44X and analogues as microtubule targeting agents

Cancer threatens human health and life. Therefore, it is particularly important to develop safe and effective antitumor drugs. Microtubules, the main component of cytoskeleton, play an important role in maintaining cell morphology, mitosis, and signal transduction, which are one of important targets of antitumor drug research and development. Colchicine binding site inhibitors have dual effects of inhibiting proliferation and destroying blood vessels. In recent years, a series of inhibitors targeting this target have been studied and some progress has been made. XRP44X has a novel structure and overcomes some disadvantages of traditional inhibitors. It is also a multifunctional molecule that regulates not only the function of tubulin but also a variety of biological pathways. Therefore, the structure, synthesis, structure-activity relationship, and biological activity of XRP44X analogues reported in recent years were summarized in this paper, to provide a useful reference for the rational design of efficient colchicine binding site inhibitors.

Development of Novel Isatin-Tethered Quinolines as Anti-Tubercular Agents against Multi and Extensively Drug-Resistant Mycobacterium tuberculosis

We describe the design and synthesis of two isatin-tethered quinolines series (Q6a-h and Q8a-h), in connection with our research interest in developing novel isatin-bearing anti-tubercular candidates. In a previous study, a series of small molecules bearing a quinoline-3-carbohydrazone moiety was developed as anti-tubercular agents, and compound IV disclosed the highest potency with MIC value equal to 6.24 µg/mL. In the current work, we adopted the bioisosteric replacement approach to replace the 3,4,5-trimethoxy-benzylidene moiety in the lead compound IV with the isatin motif, a privileged scaffold in the TB drug discovery, to furnish the first series of target molecules Q6a-h. Thereafter, the isatin motif was N-substituted with either a methyl or benzyl group to furnish the second series Q8a-h. All of the designed quinoilne-isatin conjugates Q6a-h and Q8a-h were synthesized and then biologically assessed for anti-tubercular actions towards drug-susceptible, MDR, and XDR strains. Superiorly, the N-benzyl-bearing compound Q8b possessed the best activities against the examined M. tuberculosis strains with MICs equal 0.06, 0.24, and 1.95 µg/mL, respectively.

Recent Advances of Tubulin Inhibitors Targeting the Colchicine Binding Site for Cancer Therapy

Cancer accounts for numerous deaths each year, and it is one of the most common causes of death worldwide, despite many breakthroughs in the discovery of novel anticancer candidates. Each new year the FDA approves the use of new drugs for cancer treatments. In the last years, the biological targets of anticancer agents have started to be clearer and one of these main targets is tubulin protein; this protein plays an essential role in cell division, as well as in intracellular transportation. The inhibition of microtubule formation by targeting tubulin protein induces cell death by apoptosis. In the last years, numerous novel structures were designed and synthesized to target tubulin, and this can be achieved by inhibiting the polymerization or depolymerization of the microtubules. In this review article, recent novel compounds that have antiproliferation activities against a panel of cancer cell lines that target tubulin are explored in detail. This review article emphasizes the recent developments of tubulin inhibitors, with insights into their antiproliferative and anti-tubulin activities. A full literature review shows that tubulin inhibitors are associated with properties in the inhibition of cancer cell line viability, inducing apoptosis, and good binding interaction with the colchicine binding site of tubulin. Furthermore, some drugs, such as cabazitaxel and fosbretabulin, have been approved by FDA in the last three years as tubulin inhibitors. The design and development of efficient tubulin inhibitors is progressively becoming a credible solution in treating many species of cancers.

Design, synthesis and molecular docking of new fused 1H-pyrroles, pyrrolo[3,2-d]pyrimidines and pyrrolo[3,2-e][1, 4]diazepine derivatives as potent EGFR/CDK2 inhibitors

A new series of 1H-pyrrole (6a-c, 8a-c), pyrrolo[3,2-d]pyrimidines (9a-c) and pyrrolo[3,2-e][1, 4]diazepines (11a-c) were designed and synthesised. These compounds were designed to have the essential pharmacophoric features of EGFR Inhibitors, they have shown anticancer activities against HCT116, MCF-7 and Hep3B cancer cells with IC₅₀ values ranging from 0.009 to 2.195 µM. IC₅₀ value of doxorubicin is 0.008 µM, compounds 9a and 9c showed IC₅₀ values of 0.011 and 0.009 µM respectively against HCT-116 cells. Compound 8b exerted broad-spectrum activity against all tested cell lines with an IC₅₀ value less than 0.05 µM. Compound 8b was evaluated against a panel of kinases. This compound potently inhibited CDK2/Cyclin A1, DYRK3 and GSK3 alpha kinases with 10-23% compared to imatinib (1-10%). It has also arrested the cell cycle of MCF-7 cells at the S phase. Its antiproliferative activity was further augmented by molecular docking into the active sites of EGFR and CDK2 cyclin A1.

Anti-cancer and immunomodulatory evaluation of new nicotinamide derivatives as potential VEGFR-2 inhibitors and apoptosis inducers: in vitro and in silico studies

New nicotinamide derivatives 6, 7, 10, and 11 were designed and synthesised based on the essential features of the VEGFR-2 inhibitors. Compound 10 revealed the highest anti-proliferative activities with IC₅₀ values of 15.4 and 9.8 µM against HCT-116 and HepG2, respectively compared to sorafenib (IC₅₀ = 9.30 and 7.40 µM). Compound 7 owned promising cytotoxic activities with IC₅₀ values of 15.7 and 15.5 µM against the same cell lines, respectively. Subsequently, the VEGFR-2 inhibitory activities were assessed for the titled compounds to exhibit VEGFR-2 inhibition with sub-micromolar IC₅₀ values. Moreover, compound 7 induced the cell cycle cessation at the cycle at %G2-M and G0-G1phases, and induced apoptosis in the HCT-116. Compounds 7 and 10 reduced the levels of TNF-α by 81.6 and 84.5% as well as IL-6 by 88.4 and 60.9%, respectively, compared to dexamethasone (82.4 and 93.1%). In silico docking, molecular dynamics simulations, ADMET, and toxicity studies were carried out.

New benzoxazole derivatives as potential VEGFR-2 inhibitors and apoptosis inducers: design, synthesis, anti-proliferative evaluation, flowcytometric analysis, and in silico studies

A new series of benzoxazole derivatives were designed and synthesised to have the main essential pharmacophoric features of VEGFR-2 inhibitors. Cytotoxic activities were evaluated for all derivatives against two human cancer cell lines, MCF-7 and HepG2. Also, the effect of the most cytotoxic derivatives on VEGFR-2 protein concentration was assessed by ELISA. Compounds 14o, 14l, and 14b showed the highest activities with VEGFR-2 protein concentrations of 586.3, 636.2, and 705.7 pg/ml, respectively. Additionally, the anti-angiogenic property of compound 14b against human umbilical vascular endothelial cell (HUVEC) was performed using a wound healing migration assay. Compound 14b reduced proliferation and migratory potential of HUVEC cells. Furthermore, compound 14b was subjected to further biological investigations including cell cycle and apoptosis analyses. Compound 14b arrested the HepG2 cell growth at the Pre-G1 phase and induced apoptosis by 16.52%, compared to 0.67% in the control (HepG2) cells. The effect of apoptosis was buttressed by a 4.8-fold increase in caspase-3 level compared to the control cells. Besides, different in silico docking studies were also performed to get better insights into the possible binding mode of the target compounds with VEGFR-2 active sites.

Design, synthesis and biological evaluation of novel diarylpyridine derivatives as tubulin polymerisation inhibitors

A set of novel diarylpyridines as anti-tubulin agents were designed, synthesised using a rigid pyridine as a linker to fix the cis-orientation of ring-A and ring-B. All of the target compounds were evaluated for their in vitro antiproliferative activities. Among them, 10t showed remarkable antiproliferative activities against three cancer cell lines (HeLa, MCF-7 and SGC-7901) in sub-micromolar concentrations. Consistent with its potent antiproliferative activity, 10t also displayed potent anti-tubulin activity. Cellular mechanism investigation elucidated 10t disrupted the cellular microtubule structure, arrested cell cycle at G2/M phase and induces apoptosis. Molecular modelling studies showed that 10t could bind to the colchicine binding site on microtubules. These results provide motivation and further guidance for the development of new CA-4 analogues.

Tetrahydroquinolinone derivatives exert antiproliferative effect on lung cancer cells through apoptosis induction

The anticancer properties of quinolones is a topic of interest among researchers in the scientific world. Because these compounds do not cause side effects, unlike the commonly used cytostatics, they are considered a promising source of new anticancer drugs. In this work, we designed a brief synthetic pathway and obtained a series of novel 8-phenyltetrahydroquinolinone derivatives functionalized with benzyl-type moieties at position 3. The compounds were synthesized via classical reactions such as nucleophilic substitution, solvent lysis, and condensation. Biological evaluation revealed that 3-(1-naphthylmethyl)-4-phenyl-5,6,7,8-tetrahydro-1H-quinolin-2-one (4a) exhibited potent cytotoxicity toward colon (HTC-116) and lung (A549) cancer cell lines. Analysis of the mechanism of action of compounds showed that compound 4a induced cell cycle arrest at the G2/M phase, leading to apoptotic cell death via intrinsic and extrinsic pathways. Taken together, the findings of the study suggest that tetrahydroquinolinone derivatives bearing a carbonyl group at position 2 could be potential lead compounds to develop anticancer agents for the treatment of lung cancers.

Design, synthesis and biological evaluation of 9-aryl-5H-pyrido[4,3-b]indole derivatives as potential tubulin polymerization inhibitors

A series of new 9-aryl-5H-pyrido[4,3-b]indole derivatives as tubulin polymerization inhibitors were designed, synthesized, and evaluated for antitumor activity. All newly prepared compounds were tested for their anti-proliferative activity in vitro against three different cancer cells (SGC-7901, HeLa, and MCF-7). Among the designed compounds, compound 7k displayed the strongest anti-proliferative activity against HeLa cells with IC₅₀ values of 8.7 ± 1.3 μM. In addition, 7k could inhibit the polymerization of tubulin and disrupt the microtubule network of cells. Further mechanism studies revealed that 7k arrested cell cycle at the G2/M phase and induced apoptosis in a dose-dependent manner. Molecular docking analysis confirmed that 7k may bind to colchicine binding sites on microtubules. Our study aims to provide a new strategy for the development of antitumor drugs targeting tubulin.

Antiproliferative Potential of Gloriosine: A Lead for Anticancer Drug Development

Gloriosine, a colchicine-like natural product, is widely obtained from Gloriosa superba roots. Despite having remarkable anticancer potential, colchicine could not pave its way to the clinic, while gloriosine is yet to be investigated for its pharmacological effects. In the present work, 14 compounds, including gloriosine, were isolated from the G. superba roots and were characterized by NMR spectroscopy. Gloriosine (11) was evaluated for its antiproliferative activity against a panel of 15 human cancer cell lines of different tissues and normal breast cells. Gloroisine (11) displayed significant antiproliferative activity against various cancer cell lines selectively, with IC₅₀ values ranging from 32.61 to 100.28 nM. Further, gloriosine (11) was investigated for its apoptosis-inducing ability and found to form apoptotic bodies. It also inhibited A549 cell migration in the wound healing assay. Finally, molecular docking studies were performed to explore the possible binding modes of gloriosine with the colchicine-binding site of tubulin protein. Our findings suggested that gloriosine might be a potential lead for anticancer drug discovery.

Structure-Based Virtual Screening, Docking, ADMET, Molecular Dynamics, and MM-PBSA Calculations for the Discovery of Potential Natural SARS-CoV-2 Helicase Inhibitors from the Traditional Chinese Medicine

Continuing our antecedent work against COVID-19, a set of 5956 compounds of traditional Chinese medicine have been virtually screened for their potential against SARS-CoV-2 helicase (PDB ID: 5RMM). Initially, a fingerprint study with VXG, the ligand of the target enzyme, disclosed the similarity of 187 compounds. Then, a molecular similarity study declared the most similar 40 compounds. Subsequently, molecular docking studies were carried out to examine the binding modes and energies. Then, the most appropriate 26 compounds were subjected to in silico ADMET and toxicity studies to select the most convenient inhibitors to be: (1R,2S)-ephedrine (57), (1R,2S)-norephedrine (59), 2-(4-(pyrrolidin-1-yl)phenyl)acetic acid (84), 1-phenylpropane-1,2-dione (195), 2-methoxycinnamic acid (246), 2-methoxybenzoic acid (364), (R)-2-((R)-5-oxopyrrolidin-3-yl)-2-phenylacetic acid (405), (Z)-6-(3-hydroxy-4-methoxystyryl)-4-methoxy-2H-pyran-2-one (533), 8-chloro-2-(2-phenylethyl)-5,6,7-trihydroxy-5,6,7,8-tetrahydrochromone (637), 3-((1R,2S)-2-(dimethylamino)-1-hydroxypropyl)phenol (818), (R)-2-ethyl-4-(1-hydroxy-2-(methylamino)ethyl)phenol (5159), and (R)-2-((1S,2S,5S)-2-benzyl-5-hydroxy-4-methylcyclohex-3-en-1-yl)propane-1,2-diol (5168). Among the selected 12 compounds, the metabolites, compound 533 showed the best docking scores. Interestingly, the MD simulation studies for compound 533, the one with the highest docking score, over 100 ns showed its correct binding to SARS-CoV-2 helicase with low energy and optimum dynamics. Finally, MM-PBSA studies showed that 533 bonded favorably to SARS-CoV-2 helicase with a free energy value of −83 kJ/mol. Further, the free energy decomposition study determined the essential amino acid residues that contributed favorably to the binding process. The obtained results give a huge hope to find a cure for COVID-19 through further in vitro and in vivo studies for the selected compounds.

A Multistage In Silico Study of Natural Potential Inhibitors Targeting SARS-CoV-2 Main Protease

Among a group of 310 natural antiviral natural metabolites, our team identified three compounds as the most potent natural inhibitors against the SARS-CoV-2 main protease (PDB ID: 5R84), Mpro. The identified compounds are sattazolin and caprolactin A and B. A validated multistage in silico study was conducted using several techniques. First, the molecular structures of the selected metabolites were compared with that of GWS, the co-crystallized ligand of Mpro, in a structural similarity study. The aim of this study was to determine the thirty most similar metabolites (10%) that may bind to the Mpro similar to GWS. Then, molecular docking against Mpro and pharmacophore studies led to the choice of five metabolites that exhibited good binding modes against the Mpro and good fit values against the generated pharmacophore model. Among them, three metabolites were chosen according to ADMET studies. The most promising Mpro inhibitor was determined by toxicity and DFT studies to be caprolactin A (292). Finally, molecular dynamics (MD) simulation studies were performed for caprolactin A to confirm the obtained results and understand the thermodynamic characteristics of the binding. It is hoped that the accomplished results could represent a positive step in the battle against COVID-19 through further in vitro and in vivo studies on the selected compounds.

Design, synthesis, in vitro biological assessment and molecular modeling insights for novel 3-(naphthalen-1-yl)-4,5-dihydropyrazoles as anticancer agents with potential EGFR inhibitory activity

Currently, the humanity is in a fierce battle against various health-related challenges especially those associated with human malignancies. This created the urge to develop potent and selective inhibitors for tumor cells through targeting specific oncogenic proteins possessing crucial roles in cancer progression and survive. In this respect, new series of pyrazole-thiazol-4-one hybrids (9a–p) were synthesized as potential anticancer agents. All the synthesized molecules exhibited potent antiproliferative actions against breast cancer (BC) T-47D and MDA-MB-231 cell lines with IC₅₀ ranges 3.14–4.92 and 0.62–58.01, respectively. Moreover, the most potent anti-proliferative counterparts 9g and 9k were assessed against EGFR. They displayed nanomolar inhibitory activity, IC₅₀ 267 ± 12 and 395 ± 17 nM, respectively. Worth noting, both compounds 9g and 9k induced apoptosis in MDA-MB-231 cells, and resulted in a cell cycle arrest at G2/M phase. Furthermore, an in silico analysis including docking and molecular dynamic simulations was performed.

New [1,2,4]triazolo[4,3-c]quinazoline derivatives as vascular endothelial growth factor receptor-2 inhibitors and apoptosis inducers: Design, synthesis, docking, and antiproliferative evaluation

In continuation of our previous efforts in the field of design and synthesis of vascular endothelial growth factor receptor (VEGFR)-2 inhibitors, a new series of [1,2,4]triazolo[4,3-c]quinazoline derivatives were designed and synthesized as modified analogs of some reported VEGFR-2 inhibitors. The synthesized compounds were designed to have the essential pharmacophoric features of VEGFR-2 inhibitors. Antiproliferative activities of the synthesized compounds were investigated against two tumor cell lines (HepG2 and HCT-116) using sorafenib as a positive control. Compound 10k emerged as the most promising antiproliferative agent with IC₅₀ values of 4.88 and 5.21 µM against HepG2 and HCT-116 cells, respectively. Also, it showed the highest inhibitory activity against VEGFR-2 with an IC₅₀ value of 53.81 nM compared to sorafenib (IC₅₀  = 44.34 nM). Cell cycle analysis revealed that compound 10k can arrest HepG2 cells at both the S and G2/M phases. In addition, this compound produced a tenfold increase in apoptotic cells compared to the control. Furthermore, the effect of compound 10k on the expression level of BAX, Bcl-2, and caspase-3 was assessed. This compound caused a 3.35-fold increase in BAX expression levels and a 1.25-fold reduction in Bcl-2 expression levels. The BAX/Bcl-2 ratio was calculated to be 4.57, indicating a promising apoptotic effect. It also showed a significant increase in the level of caspase-3 (4.12-fold) compared to the control cells. In silico docking, absorption, distribution, metabolism, excretion, and toxicity, and toxicity studies were performed for the synthesized compounds to investigate their binding patterns against the proposed biological target (VEGFR-2) and to assess the drug-likeness characters.

Multi-Step In Silico Discovery of Natural Drugs against COVID-19 Targeting Main Protease

In continuation of our antecedent work against COVID-19, three natural compounds, namely, Luteoside C (130), Kahalalide E (184), and Streptovaricin B (278) were determined as the most promising SARS-CoV-2 main protease (Mpro) inhibitors among 310 naturally originated antiviral compounds. This was performed via a multi-step in silico method. At first, a molecular structure similarity study was done with PRD_002214, the co-crystallized ligand of Mpro (PDB ID: 6LU7), and favored thirty compounds. Subsequently, the fingerprint study performed with respect to PRD_002214 resulted in the election of sixteen compounds (7, 128, 130, 156, 157, 158, 180, 184, 203, 204, 210, 237, 264, 276, 277, and 278). Then, results of molecular docking versus Mpro PDB ID: 6LU7 favored eight compounds (128, 130, 156, 180, 184, 203, 204, and 278) based on their binding affinities. Then, in silico toxicity studies were performed for the promising compounds and revealed that all of them have good toxicity profiles. Finally, molecular dynamic (MD) simulation experiments were carried out for compounds 130, 184, and 278, which exhibited the best binding modes against Mpro. MD tests revealed that luteoside C (130) has the greatest potential to inhibit SARS-CoV-2 main protease.

Discovery of new nicotinamides as apoptotic VEGFR-2 inhibitors: virtual screening, synthesis, anti-proliferative, immunomodulatory, ADMET, toxicity, and molecular dynamic simulation studies

A library of modified VEGFR-2 inhibitors was designed as VEGFR-2 inhibitors. Virtual screening was conducted for the hypothetical library using in silico docking, ADMET, and toxicity studies. Four compounds exhibited high in silico affinity against VEGFR-2 and an acceptable range of the drug-likeness. These compounds were synthesised and subjected to in vitro cytotoxicity assay against two cancer cell lines besides VEGFR-2 inhibitory determination. Compound D-1 showed cytotoxic activity against HCT-116 cells almost double that of sorafenib. Compounds A-1, C-6, and D-1 showed good IC₅₀ values against VEGFR-2. Compound D-1 markedly increased the levels of caspase-8 and BAX expression and decreased the anti-apoptotic Bcl-2 level. Additionally, compound D-1 caused cell cycle arrest at pre-G1 and G2-M phases in HCT-116 cells and induced apoptosis at both early and late apoptotic stages. Compound D-1 decreased the level of TNF-α and IL6 and inhibited TNF-α and IL6. MD simulations studies were performed over 100 ns.

Computational-Based Discovery of the Anti-Cancer Activities of Pyrrole-Based Compounds Targeting the Colchicine-Binding Site of Tubulin

Despite the tubulin-binding agents (TBAs) that are widely used in the clinic for cancer therapy, tumor resistance to TBAs (both inherited and acquired) significantly impairs their effectiveness, thereby decreasing overall survival (OS) and progression-free survival (PFS) rates, especially for the patients with metastatic, recurrent, and unresectable forms of the disease. Therefore, the development of novel effective drugs interfering with the microtubules' dynamic state remains a big challenge in current oncology. We report here about the novel ethyl 2-amino-1-(furan-2-carboxamido)-5-(2-aryl/tert-butyl-2-oxoethylidene)-4-oxo-4,5-dihydro-1H-pyrrole-3-carboxylates (EAPCs) exhibiting potent anti-cancer activities against the breast and lung cancer cell lines in vitro. This was due to their ability to inhibit tubulin polymerization and induce cell cycle arrest in M-phase. As an outcome, the EAPC-treated cancer cells exhibited a significant increase in apoptosis, which was evidenced by the expression of cleaved forms of PARP, caspase-3, and increased numbers of Annexin-V-positive cells. By using the in silico molecular modeling methods (e.g., induced-fit docking, binding metadynamics, and unbiased molecular dynamics), we found that EAPC-67 and -70 preferentially bind to the colchicine-binding site of tubulin. Lastly, we have shown that the EAPCs indicated above and colchicine utilizes a similar molecular mechanism to inhibit tubulin polymerization via targeting the T7 loop in the β-chain of tubulin, thereby preventing the conformational changes in the tubulin dimers required for their polymerization. Collectively, we identified the novel and potent TBAs that bind to the colchicine-binding site and disrupt the microtubule network. As a result of these events, the compounds induced a robust cell cycle arrest in M-phase and exhibited potent pro-apoptotic activities against the epithelial cancer cell lines in vitro.

Computational-Based Discovery of the Anti-Cancer Activities of Pyrrole-Based Compounds Targeting the Colchicine-Binding Site of Tubulin

Despite the tubulin-binding agents (TBAs) that are widely used in the clinic for cancer therapy, tumor resistance to TBAs (both inherited and acquired) significantly impairs their effectiveness, thereby decreasing overall survival (OS) and progression-free survival (PFS) rates, especially for the patients with metastatic, recurrent, and unresectable forms of the disease. Therefore, the development of novel effective drugs interfering with the microtubules' dynamic state remains a big challenge in current oncology. We report here about the novel ethyl 2-amino-1-(furan-2-carboxamido)-5-(2-aryl/tert-butyl-2-oxoethylidene)-4-oxo-4,5-dihydro-1H-pyrrole-3-carboxylates (EAPCs) exhibiting potent anti-cancer activities against the breast and lung cancer cell lines in vitro. This was due to their ability to inhibit tubulin polymerization and induce cell cycle arrest in M-phase. As an outcome, the EAPC-treated cancer cells exhibited a significant increase in apoptosis, which was evidenced by the expression of cleaved forms of PARP, caspase-3, and increased numbers of Annexin-V-positive cells. By using the in silico molecular modeling methods (e.g., induced-fit docking, binding metadynamics, and unbiased molecular dynamics), we found that EAPC-67 and -70 preferentially bind to the colchicine-binding site of tubulin. Lastly, we have shown that the EAPCs indicated above and colchicine utilizes a similar molecular mechanism to inhibit tubulin polymerization via targeting the T7 loop in the β-chain of tubulin, thereby preventing the conformational changes in the tubulin dimers required for their polymerization. Collectively, we identified the novel and potent TBAs that bind to the colchicine-binding site and disrupt the microtubule network. As a result of these events, the compounds induced a robust cell cycle arrest in M-phase and exhibited potent pro-apoptotic activities against the epithelial cancer cell lines in vitro.

Synthesis of Benzalacetophenone Based Isoxazoline and Isoxazole Derivatives

Abstract:

The demand for natural product based drugs with less cost and efficient procedures has become a challenge to researchers. Benzalacetophenone is a natural product based species that is modified into numerous heterocyclic compounds including isoxazoline and isoxazole derivatives. The utility of isoxazoline and oxazole derivatives has been increased for the synthesis of the new and effective chemical entities to serve medicinal chemistry in the past few years. Isoxazoline and isoxazole are fascinating classes of heterocyclic compounds, which belong to N- and O-heterocycles, and are widely used as precursors for the development of drugs. This review highlights the recent work for the synthesis of mono and bis isoxazoline and isoxazole derivatives using stable benzalacetophenone and functionalization of isoxazoline and isoxazole, along with the prevailing biological properties.

Characterization, in-silico, and in-vitro study of a new steroid derivative from Ophiocoma dentata as a potential treatment for COVID-19

The medicinal potential of marine invertebrates' bioactive components that may act as anti-COVID-19 demonstrated promising results. Ophiocoma dentata, which is common in the Red Sea, is one such source. Therefore, this study aimed to isolate a new compound from the brittle star, Ophiocoma dentata, and evaluate its efficacy as anti-COVID-19 in-silico and in-vitro. Standard procedures were followed in order to assess the isolated compound's preliminary toxicity and anti-inflammatory properties. Computer virtual screening technology through molecular docking and ADMET studies was conducted as well as a new steroid derivative was isolated for the first time, named 5α-cholesta-4(27), 24-dien-3β, 23 β-diol. Investigation of the Anti-Covid-19 activity of the isolated compound using a Plaque reduction assay revealed 95% inhibition at a concentration of 5 ng/µl (12.48 µM). Moreover, this compound showed an IC50 of 11,350 ± 1500 ng/ml against the normal fibroblast cells, indicating its safety. Interestingly, this compound exhibited anti-inflammatory activity with an IC50 of 51.92 ± 0.03 μg/ml compared to a reference drug's IC50 of 53.64 ± 0.01 μg/ml, indicating that this compound is a potent anti-inflammatory. In silico data have proved that the isolated compound is a promising viral inhibitor against SARS-CoV2 and is thus recommended as a future nature preventive and curative antiviral drug.

Multi-Phase In Silico Discovery of Potential SARS-CoV-2 RNA-Dependent RNA Polymerase Inhibitors among 3009 Clinical and FDA-Approved Related Drugs

Proceeding our prior studies of SARS-CoV-2, the inhibitory potential against SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) has been investigated for a collection of 3009 clinical and FDA-approved drugs. A multi-phase in silico approach has been employed in this study. Initially, a molecular fingerprint experiment of Remdesivir (RTP), the co-crystallized ligand of the examined protein, revealed the most similar 150 compounds. Among them, 30 compounds were selected after a structure similarity experiment. Subsequently, the most similar 30 compounds were docked against SARS-CoV-2 RNA-dependent RNA polymerase (PDB ID: 7BV2). Aloin 359, Baicalin 456, Cefadroxil 1273, Sophoricoside 1459, Hyperoside 2109, and Vitexin 2286 exhibited the most precise binding modes, as well as the best binding energies. To confirm the obtained results, MD simulations experiments have been conducted for Hyperoside 2109, the natural flavonoid glycoside that exhibited the best docking scores, against RdRp (PDB ID: 7BV2) for 100 ns. The achieved results authenticated the correct binding of 2109, showing low energy and optimum dynamics. Our team presents these outcomes for scientists all over the world to advance in vitro and in vivo examinations against COVID-19 for the promising compounds.

Regioselective approach to colchiceine tropolone ring functionalization at C(9) and C(10) yielding new anticancer hybrid derivatives containing heterocyclic structural motifs

The influence of base type, temperature, and solvent on regioselective C(9)/C(10) “click” modifications within the tropolone ring of colchiceine (2) is investigated. New ether derivatives of 2, bearing alkyne, azide, vinyl, or halide aryl groups enable assembly of the alkaloid part with heterocycles or important biomolecules such as saccharides, geldanamycin or AZT into hybrid scaffolds by dipolar cycloaddition (CuAAC) or Heck reaction. Compared to colchicine (1) or colchiceine (2), ether congeners, as e.g. 3e [IC₅₀s_(3e) ∼ 0.9 nM], show improved or similar anticancer effects, whereby the bulkiness of the substituents and the substitution pattern of the tropolone proved to be essential. Biological studies reveal that expanding the ether arms by terminal basic heterocycles as quinoline or pyridine, decreases the toxicity in HDF cells at high anticancer potency (IC₅₀s ∼ 1–2 nM). Docking of ether and hybrid derivatives into the colchicine pocket of α_GTP/β tubulin dimers reveals a relationship between the favourable binding mode and the attractive anticancer potency.

Targeting VEGFR-2 by new quinoxaline derivatives: Design, synthesis, antiproliferative assay, apoptosis induction, and in silico studies

Twelve new triazolo[4,3-a]quinoxaline-based compounds are reported as anticancer agents with potential effects against vascular endothelial growth factor receptor-2 (VEGFR-2), using sorafenib as a reference molecule. With sorafenib as the positive control, the antiproliferative effects of the synthesized compounds against MCF-7 and HepG2 cells, as well as their VEGFR-2-inhibitory activities, were assessed. The most powerful VEGFR-2 inhibitor was compound 14a, which had an IC₅₀ value of 3.2 nM, which is very close to that of sorafenib (IC₅₀  = 3.12 nM). Furthermore, compounds 14c and 15d showed potential inhibitory activity against VEGFR-2, with IC₅₀ values of 4.8 and 5.4 nM, respectively. Compound 14a caused apoptosis in HepG2 cells and stopped the cell cycle at the G2/M phase. In HepG2 cells, it also increased the levels of the proteases caspase-3 and caspase-9, as well as the Bax/Bcl-2 ratio. In silico ADMET (absorption, distribution, metabolism, excretion, and toxicity) and toxicity experiments revealed that the synthesized agents had acceptable drug-likeness.

Discovery of N-aryl sulphonamide-quinazoline derivatives as anti-gastric cancer agents in vitro and in vivo via activating the Hippo signalling pathway

Hippo signalling pathway plays a crucial role in tumorigenesis and cancer progression. In this work, we identified an N-aryl sulphonamide-quinazoline derivative, compound 9i as an anti-gastric cancer agent, which exhibited potent antiproliferative ability with IC50 values of 0.36 μM (MGC-803 cells), 0.70 μM (HCT-116 cells), 1.04 μM (PC-3 cells), and 0.81 μM (MCF-7 cells), respectively and inhibited YAP activity by the activation of p-LATS. Compound 9i was effective in suppressing MGC-803 xenograft tumour growth in nude mice without obvious toxicity and significantly down-regulated the expression of YAP in vivo. Compound 9i arrested cells in the G2/M phase, induced intrinsic apoptosis, and inhibited cell colony formation in MGC-803 and SGC-7901 cells. Therefore, compound 9i is to be reported as an anti-gastric cancer agent via activating the Hippo signalling pathway and might help foster a new strategy for the cancer treatment by activating the Hippo signalling pathway regulatory function to inhibit the activity of YAP.

Tertiary sulphonamide derivatives as dual acting small molecules that inhibit LSD1 and suppress tubulin polymerisation against liver cancer

A series of tertiary sulphonamide derivatives were synthesised and evaluated for their antiproliferative activity against liver cancer cell lines (SNU-475, HepG-2, and Bel-7402). Among these tertiary sulphonamides, compound 17a displayed the best anti-liver cancer activity against Bel-7402 cells with an IC50 value of 0.32 μM. Compound 17a could effectively inhibit tubulin polymerisation with an IC50 value of 1.27 μM. Meanwhile, it selectively suppressed LSD1 with an IC50 value of 63 nM. It also concentration-dependently inhibited migration against Bel-7402 cells. Importantly, tertiary sulphonamide 17a exhibited the potent antitumor activity in vivo. All these findings revealed that compound 17a might be a tertiary sulphonamide-based dual inhibitor of tubulin polymerisation and LSD1 to treat liver cancer.

Inhibition of Vascular Smooth Muscle and Cancer Cell Proliferation by New VEGFR Inhibitors and Their Immunomodulator Effect: Design, Synthesis, and Biological Evaluation

Abnormal vascular smooth muscle cell (VSMC) proliferation has an important role in the pathogenesis of both atherosclerosis restenosis and hypertension. Vascular endothelial growth factor (VEGF) has been shown to stimulate VSMC proliferation. In addition, angiogenesis is one of the hallmarks of cancerous growth. VEGF is the key modulator for the initial stages of angiogenesis that acts through the endothelial-specific receptor tyrosine kinases (VEGFRs). VEGFR-2 blockage is a good approach for suppression of angiogenesis. In order to discover novel VEGFR-2 TK inhibitors, we have designed and synthesized three new series of pyridine-containing compounds. The new compounds were all screened against a panel of three cell lines (HepG-2, HCT-116, and MCF-7). Promising results encouraged us to additionally evaluate the most active members for their in vitro VEGFR-2 inhibitory effect. Compound 7a, which is the most potent candidate, revealed a significant increase in caspase-3 level by 7.80-fold when compared to the control. In addition, Bax and Bcl-2 concentration levels showed an increase in the proapoptotic protein Bax (261.4 Pg/ml) and a decrease of the antiapoptotic protein Bcl-2 (1.25 Pg/ml) compared to the untreated cells. Furthermore, compound 7a arrested the cell cycle in the G2/M phase with induction of apoptosis. The immunomodulatory effect of compound 7a, the most active member, showed a reduction in TNF-α by 87%. Also, compound 7a caused a potent inhibitory effect on smooth muscle proliferation. Docking studies were also performed to get better insights into the possible binding mode of the target compounds with VEGFR-2 active sites.

In Silico Exploration of Potential Natural Inhibitors against SARS-Cov-2 nsp10

In continuation of our previous effort, different in silico selection methods were applied to 310 naturally isolated metabolites that exhibited antiviral potentialities before. The applied selection methods aimed to pick the most relevant inhibitor of SARS-CoV-2 nsp10. At first, a structural similarity study against the co-crystallized ligand, S-Adenosyl Methionine (SAM), of SARS-CoV-2 nonstructural protein (nsp10) (PDB ID: 6W4H) was carried out. The similarity analysis culled 30 candidates. Secondly, a fingerprint study against SAM preferred compounds 44, 48, 85, 102, 105, 182, 220, 221, 282, 284, 285, 301, and 302. The docking studies picked 48, 182, 220, 221, and 284. While the ADMET analysis expected the likeness of the five candidates to be drugs, the toxicity study preferred compounds 48 and 182. Finally, a density-functional theory (DFT) study suggested vidarabine (182) to be the most relevant SARS-Cov-2 nsp10 inhibitor.

Identification of new [1,2,4]triazolo[4,3-a]quinoxalines as potent VEGFR-2 tyrosine kinase inhibitors: Design, synthesis, anticancer evaluation, and in silico studies

Tumor angiogenesis is mainly regulated by VEGFR-2. In this study, a new series of [1,2,4]triazolo[4,3-a]quinoxaline based-derivatives has been designed and synthesized to develop new anti-proliferative and anti-VEGFR-2 members. Anti-proliferative activities of the synthesized compounds were tested against MCF-7 and HepG2 cell lines. Compound 19a exhibited the highest activity towards both MCF-7 and HepG2 cell lines (IC₅₀ = 8.2 and 5.4 µM, respectively), compared to sorafenib (IC₅₀ = 3.51 and 2.17 µM, respectively). Additionally, all compounds were screened to evaluate their effect as VEGFR-2 inhibitors. Compound 19a (IC₅₀ = 3.4 nM) exhibited good activity compared to sorafenib (IC₅₀ = 3.12 nM). Furthermore, compound 19a disrupted the HepG2 cell cycle by arresting the G2/M phase. Also, marked increase in the percentage apoptotic cells was achieved by compound 19a. The induced apoptotic effect of compound 19a in HepG2 cells was assured by increased pro-apoptotic marker (Bax) expression by 2.33-fold and decreased anti-apoptotic (Bcl-2) expression by 1.88-fold, resulting in an elevation of the Bax/Bcl-2 ratio in HepG2 cells. Comparing to the control cells, compound 19a induced an increase in expression of cleaved caspase-3 and caspase-9 by 2.44- and 2.69-fold, respectively. Finally, the binding modes of the target derivatives were investigated through docking studies against the proposed molecular target (VEGFR-2, PDB ID: 2OH4).

New quinoxaline-based VEGFR-2 inhibitors: design, synthesis, and antiproliferative evaluation with in silico docking, ADMET, toxicity, and DFT studies

A new series of 3-methylquinoxaline-based derivatives having the same essential pharmacophoric features as VEGFR-2 inhibitors have been synthesized and evaluated for their antiproliferative activities against two human cancer cell lines, MCF-7 and HepG-2. Compounds 15b and 17b demonstrated a significant antiproliferative effect with IC₅₀ ranging from 2.3 to 5.8 μM. An enzymatic assay was carried out for all the tested candidates against VEGFR-2. Compound 17b was the most potent VEGFR-2 inhibitor (IC₅₀ = 2.7 nM). Mechanistic investigation including cell cycle arrest and apoptosis was performed for compound 17b against HepG-2 cells, and the results revealed that 17b induced cell apoptosis and arrested cell cycle in the G2/M phase. Moreover, apoptosis analyses were conducted for compound 17b to evaluate its apoptotic potential. The results showed upregulation in caspase-3 and caspase-9 levels, and improving the Bax/Bcl-2 ratio by more than 10-fold. Docking studies were performed to determine the possible interaction with the VEGFR-2 active site. Further docking studies were carried out for compound 17b against cytochrome P450 to present such compounds as non-inhibitors. In silico ADMET, toxicity, and physico-chemical properties revealed that most of the synthesized members have acceptable values of drug-likeness. Finally, DFT studies were carried out to calculate the thermodynamic, molecular orbital and electrostatic potential properties.

New quinoxaline-2(1H)-ones as potential VEGFR-2 inhibitors: design, synthesis, molecular docking, ADMET profile and anti-proliferative evaluations

Eleven new quinoxaline derivatives were designed and synthesized as modified VEGFR-2 inhibitors of our previous work.