Application of triazoles as bioisosteres and linkers in the development of microtubule targeting agents

Average Electron Density: A Quantitative Tool for Evaluating Non-Classical Bioisosteres of Amides

Bioisosterism is strategically used in drug design to enhance the pharmacokinetic and pharmacodynamic properties of therapeutic molecules. The average electron density (AED) tool has been used in several studies to quantify similarities among nonclassical bioisosteres of carboxylic acid. In this study, the AED tool is used to quantify the similarities among nonclassical bioisosteres of an amide group. In particular, amide-to-1,2,3-triazole bioisosterism is considered. To evaluate the AED differences exhibited by isomers of nonclassical bioisosteres, both isomers of amide (cis and trans) and 1,2,3-triazole (1,4 and 1,5 disubstituted moieity) were considered. The amide and 1,2,3-triazole bioisosteric moieties were capped with various R groups (R= methyl, hydrogen, and chloro) to account for changes in their environment. Amide-to-triazole bioisosteric substitutions were then explored in a more realistic environment, that is, within the FDA-approved anticancer imatinib drug. The AED tool effectively identified similarities between substantially different moieties, 1,2,3-triazole and amide, showing AED differences of no more than 4%. The AED tool was also proven to be useful in evaluating the contribution of various factors affecting triazole-amide bioisosterism including isomerism and changes in their environment. The AED values of each bioisostere were transferable within a maximum difference of 2.6%, irrespective of the change in environment. The 1,4- and 1,5-disubstituted isomers of 1,2,3-triazole have AED values that differ by less than unity, 0.52%. Similarly, the AED values of the cis- and trans-amide isomers differ by only 1.31%. Overall, the AED quantitative tool not only replicated experimental observations regarding similarities in bioisosteres, but also explained and quantified each contributing factor. This demonstrates the extended utility of the AED tool from nonclassical carboxylic acid bioisosteres to amide equivalents.On the contrary, electrostatic potential maps, usually used in the literature to qualitatively evaluate bioisosterism, were not similar for the 1,2,3-triazole and amide bioisosteres, under different environments. Overall, the AED tool proves to be powerful in quantitatively evaluating and predicting bioisosterism across diverse moieties considering structural and environmental variations, making it valuable in drug design.

Peptide-ligand conjugate based immunotherapeutic approach for targeted dismissal of non-structural protein 1 of dengue virus: A novel therapeutic solution for mild and severe dengue infections

Dengue virus infection has significantly increased, with reported cases soaring from 505,430 in 2000 to 2,809,818 in 2022, emphasizing the need for effective treatments. Among the eleven structural and non-structural proteins of DENV, Non-structural protein 1 (NS1) has emerged as a promising target due to its diverse role in modulating the immune response, inducing vascular leakage, and facilitating viral replication and assembly. Monoclonal antibodies are the sole therapeutics to target NS1, but concerns about their cross-reactivity persist. Given these concerns, our study focuses on designing a novel Peptide Ligand Conjugate (PLC) as a potential alternative immunotherapeutic agent against NS1. This PLC aims to mediate the immune elimination of soluble NS1 and NS1-presenting DENV-infected host cells by pre-existing vaccine-induced immunity. By employing the High Throughput Virtual Screening (HTVS) method, QikProp analysis, and Molecular Dynamics studies, we identified three hits from Asinex Biodesigned Ligands out of 220,177 compounds that show strong binding affinity towards the monoclonal binding site of NS1 protein. After a rigorous analysis of physicochemical characteristics, antigenicity, allergenicity, and toxicity using various servers, we selected two peptides: the minimum epitopic region of the Diphtheria and Tetanus toxins as the peptide components of the PLCs. A non-cleavable, non-reactive oxime linker connected the ligand with the peptide through oxime and amide bonds. DPT vaccine is widely used in dengue-endemic countries, and it has been reported that antibodies titer against MER of Diphtheria toxin and Tetanus toxins persist lifelong in DPT-vaccinated people. Therefore, once the rationally designed PLCs bind to NS1 through the ligands, the peptide will induce an immune response against NS1 by triggering pre-existing DPT antibodies and activating memory cells. This orchestrated immune response will destroy soluble NS1 and NS1-expressing DENV-infected cells, thereby reducing the illness of severe dengue hemorrhagic fever and the DENV infection, respectively. Given the increasing demand for new therapeutics for DENV treatment, further investigation into this novel immune-therapeutic strategy may offer a new avenue for treating mild and severe dengue infections.

Identified Isosteric Replacements of Ligands' Glycosyl Domain by Data Mining

Biologically equivalent replacements of key moieties in molecules rationalize scaffold hopping, patent busting, or R-group enumeration. Yet, this information may depend upon the expert-defined space, and might be subjective and biased toward the chemistries they get used to. Most importantly, these practices are often informatively incomplete since they are often compromised by a try-and-error cycle, and although they depict what kind of substructures are suitable for the replacement occurrence, they fail to explain the driving forces to support such interchanges. The protein data bank (PDB) encodes a receptor-ligand interaction pattern and could be an optional source to mine structural surrogates. However, manual decoding of PDB has become almost impossible and redundant to excavate the bioisosteric know-how. Therefore, a text parsing workflow has been developed to automatically extract the local structural replacement of a specific structure from PDB by finding spatial and steric interaction overlaps between the fragments in endogenous ligands and particular ligand fragments. Taking the glycosyl domain for instance, a total of 49 520 replacements that overlap on nucleotide ribose were identified and categorized based on their SMILE codes. A predominately ring system, such as aliphatic and aromatic rings, was observed; yet, amide and sulfonamide replacements also occur. We believe these findings may enlighten medicinal chemists on the structure design and optimization of ligands using the bioisosteric replacement strategy.

Identification of multidentate tyrosyl-DNA phosphodiesterase 1 (TDP1) inhibitors that simultaneously access the DNA, protein and catalytic-binding sites by oxime diversification

Tyrosyl-DNA phosphodiesterase 1 (TDP1) is a member of the phospholipase D family that can downregulate the anticancer effects of the type I topoisomerase (TOP1) inhibitors by hydrolyzing the 3'-phosphodiester bond between DNA and the TOP1 residue Y723 in the critical stalled intermediate that is the foundation of TOP1 inhibitor mechanism of action. Thus, TDP1 antagonists are attractive as potential enhancers of TOP1 inhibitors. However, the open and extended nature of the TOP1-DNA substrate-binding region has made the development of TDP1 inhibitors extremely challenging. In this study, starting from our recently identified small molecule microarray (SMM)-derived TDP1-inhibitory imidazopyridine motif, we employed a click-based oxime protocol to extend the parent platform into the DNA and TOP1 peptide substrate-binding channels. We applied one-pot Groebke-Blackburn-Bienayme multicomponent reactions (GBBRs) to prepare the needed aminooxy-containing substrates. By reacting these precursors with approximately 250 aldehydes in microtiter format, we screened a library of nearly 500 oximes for their TDP1 inhibitory potencies using an in vitro florescence-based catalytic assay. Select hits were structurally explored as their triazole- and ether-based isosteres. We obtained crystal structures of two of the resulting inhibitors bound to the TDP1 catalytic domain. The structures reveal that the inhibitors form hydrogen bonds with the catalytic His-Lys-Asn triads ("HKN" motifs: H263, K265, N283 and H493, K495, N516), while simultaneously extending into both the substrate DNA and TOP1 peptide-binding grooves. This work provides a structural model for developing multivalent TDP1 inhibitors capable of binding in a tridentate fashion with a central component situated within the catalytic pocket and extensions that project into both the DNA and TOP1 peptide substrate-binding regions.

Development of Novel Pt(IV)-Carbohydrate Derivatives as Targeted Anticancer Agents against Osteosarcoma

Despite the enormous importance of cisplatin as a chemotherapeutic agent, its application is impacted by dose-limiting side effects and lack of selectivity for cancer cells. Researchers can overcome these issues by taking advantage of the pro-drug nature of the platinum(IV) oxidation state, and by modifying the coordination sphere of the metal centre with specific vectors whose receptors are overexpressed in tumour cell membranes (e.g., carbohydrates). In this paper we report the synthesis of four novel carbohydrate-modified Pt(IV) pro-drugs, based on the cisplatin scaffold, and their biological activity against osteosarcoma (OS), a malignant tumour which is most common in adolescents and young adults. The carbohydrate-targeting vectors and Pt scaffold are linked using copper-catalysed azide-alkyne cycloaddition (CuAAC) chemistry, which is synonymous with mild and robust reaction conditions. The novel complexes are characterised using multinuclear 1D-2D NMR (¹H, ¹³C and ¹⁹⁵Pt), IR, HR-MS, Elem. Analyses, and CV. Cytotoxicity on 2D and 3D and cell morphology studies on OS cell lines, as well as non-cancerous human foetal osteoblasts (hFOBs), are discussed.

Erlotinib-Modified BODIPY Photosensitizers for Targeted Photodynamic Therapy

Photodynamic therapy (PDT) is an innovative, non-invasive and highly selective therapeutic modality for tumours and non-malignant diseases. BODIPY based molecules can function as new generation photosensitizers (PSs) in various PDT applications. Despite numerous conjugated PS systems are available, BODIPYs containing erlotinib lagged behind other photosensitizer units. In this study, smart photosensitizers containing BODIPY, erlotinib and hydrophilic units were prepared for the first time, their physicochemical properties and PDT effects were investigated. Compared with non-halogenated compound, halogenated derivatives possessed much lower fluorescence profile as well as the good ROS generation ability under red light. In vitro PDT studies were performed on both healthy (PNT1a) and prostate cancerous cells (PC3) to determine the selectivity of the compounds on cancerous cells and their effects under light. The halogenated conjugates, exposed to low dose of light illumination exhibited potent activity on cancer cell viability and the calculated IC₅₀ values proved the high phototoxicity of the photosensitizers. It was also determined that the PSs have very low dark toxicity and that the light illumination and ROS formation are required for the initiation of the cell death mechanism. As a result, erlotinib modified BODIPYs could serve as promising agents in anticancer photodynamic therapy.

Thermo-Responsive Polymer-siRNA Conjugates Enabling Artificial Control of Gene Silencing around Body Temperature

PURPOSE

Controlling small interfering RNA (siRNA) activity by external stimuli is useful to exert a selective therapeutic effect at the target site. This study aims to develop a technology to control siRNA activity in a thermo-responsive manner, which can be utilized even at temperatures close to body temperature.

METHODS

siRNA was conjugated with a thermo-responsive copolymer that was synthesized by copolymerization of N-isopropylacrylamide (NIPAAm) and hydrophilic N,N-dimethylacrylamide (DMAA) to permit thermally controlled interaction between siRNA and an intracellular gene silencing-related protein by utilizing the coil-to-globule phase transition of the copolymer. The composition of the copolymer was fine-tuned to obtain lower critical solution temperature (LCST) around body temperature, and the phase transition behavior was evaluated. The cellular uptake and gene silencing efficiency of the copolymer-siRNA conjugates were then investigated in cultured cells.

RESULTS

The siRNA conjugated with the copolymer with LCST of 38.0°C exhibited ~ 11.5 nm of the hydrodynamic diameter at 37°C and ~ 9.8 nm of the diameter at 41°C, indicating the coil-globule transition above the LCST. In line with this LCST behavior, its cellular uptake and gene silencing efficiency were enhanced when the temperature was increased from 37°C to 41°C.

CONCLUSION

By fine-tuning the LCST behavior of the copolymer that was conjugated with siRNA, siRNA activity could be controlled in a thermo-responsive manner around the body temperature. This technique may offer a promising approach to induce therapeutic effects of siRNA selectively in the target site even in the in vivo conditions.

Synthesis of 4-Hydroxycoumarin-Based Triazoles/Oxadiazoles as Novel Anticancer Agents

A series of novel 3-substituted-4-hydroxycoumarins 7 and 8 containing (5-aryl-1,3,4-oxadiazol-2-yl)thio or (4-amino-5-aryl-4H-1,2,4-triazol-3-yl)thio moieties have been synthesized and evaluated as anticancer agents. The in vitro MTT assay of compounds against hepatocellular carcinoma (HepG2), breast cancer (MCF7) cells, and a human colorectal adenocarcinoma cell line with epithelial morphology (HT29) indicated that the HepG2 cells had more susceptibility to the tested compounds. Indeed, all compounds (with the exception of 7b, 7c, 7g, and 8g) were more potent than the standard drug doxorubicin against HepG2 cells (IC₅₀ values=1.65-3.83 μM). Although, the better result was obtained with the oxadiazole analog 7h against HepG2 (IC₅₀ =1.65 μM), the N-amino-triazole derivatives 8c, 8e, 8f and, 8h with IC₅₀ values of 1.78-6.34 μM showed potent activity against all tested cell lines. The good drug-like properties and in vitro potency and selectivity of 4-hydroxycoumarins 8 make them as good leads for the development of new anticancer agents.

Crystal structure of 1 H -1,2,3-Triazolo[4,5- b ]-pyridin-4-ium nitrate, C 5 H 5 N 5 O 3

C5H5N5O3, orthorhombic, Pnma (no. 62), a = 13.4643(13) Å, b = 6.2866(10) Å, c = 9.1138(9) Å, V = 771.43(16) Å3, Z = 4, R gt (F) = 0.0517, wR ref (F 2) = 0.1317, T = 293 K.

Expanding the chemical space of 3(5)-functionalized 1,2,4-triazoles

An efficient approach to the gram-scale synthesis of 3(5)-substituted, 1,3- and 1,5-disubstituted 1,2,4-triazole-derived building blocks is described. The key synthetic precursors - 1,2,4-triazole-3(5)-carboxylates (20 examples, 35-89% yield) were prepared from readily available acyl hydrazides and ethyl 2-ethoxy-2-iminoacetate hydrochloride. Further transformations were performed following the convergent synthetic strategy and allowed the preparation of 1,3- and 1,5-disubstituted 1,2,4-triazole-derived esters (16 examples, 25-75% yield), 3(5)-substituted, 1,3- and 1,5-disubstituted carboxylate salts (18 examples, 78-93% yield), amides (5 examples, 82-93% yield), nitriles (5 examples, 30-85% yield), hydrazides (6 examples, 84-89% yield), and hydroxamic acids (3 examples, 73-78% yield). Considering wide applications of the 1,2,4-triazole motif in medicinal chemistry, these compounds are valuable building blocks for lead-oriented synthesis; they have also great potential for coordination chemistry.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10593-022-03064-z.

Direct Synthesis of α-Fluoro-α-Triazol-1-yl Ketones from Sulfoxonium Ylides: A One-Pot Approach

The work reported herein showcases a new route to access α-fluoro-α-triazol-1-yl ketones from sulfoxonium ylides via α-azido-α-fluoro ketone intermediates. In a one-pot, two-step sequence, the ketosulfoxonium reactant initially undergoes insertion of F⁺ and N₃^-, followed by a subsequent CuAAC reaction with arylacetylenes to install a 1,4-triazolo moiety. The approach allows for modification to both the sulfoxonium ylide and arylacetylene reactants. Fifteen examples have been reported, with yields ranging between 22% and 75%.

CDATA[Recent Advances in the Development of 1,2,3-Triazole-containing Derivatives as Potential Antifungal Agents and Inhibitors of Lanoster ol 14α-Demethylase

1,2,3-Triazole, a five-membered heterocyclic nucleus, is widely recognized as a key chromophore of great value in medicinal chemistry for delivering compounds possessing innumerable biological activities, including antimicrobial, antitubercular, antidiabetic, antiviral, antitumor, antioxidants, and anti-inflammatory activities. Mainly, in the past years, diverse conjugates carrying this biologically valuable core have been reported due to their attractive fungicidal potential and potent effects on various infective targets. Hence, hybridization of 1,2,3-triazole with other antimicrobial pharmacophores appears to be a judicious strategy to develop new effective anti-fungal candidates to combat the emergence of drug-sensitive and drug-resistant infectious diseases. Thus, the current review highlights the recent advances of this promising category of 1,2,3-triazole-containing hybrids incorporating diverse varieties of bioactive heterocycles such as conozole, coumarin, imidazole, benzimidazole, pyrazole, indole, oxindole, chromene, pyrane, quinazoline, chalcone, isoflavone, carbohydrates, and amides. It underlies their inhibition behavior against a wide array of infectious fungal species during 2015-2020.

Quinoline-triazole half-sandwich iridium(III) complexes: synthesis, antiplasmodial activity and preliminary transfer hydrogenation studies

Iridium(iii) half-sandwich complexes containing 7-chloroquinoline-1,2,3-triazole hybrid ligands were synthesised and their inhibitory activities evaluated against the Plasmodium falciparum malaria parasite. Supporting computational analysis revealed that metal coordination to the quinoline nitrogen occurs first, forming a kinetic product that, upon heating over time, forms a more stable cyclometallated thermodynamic product. Single crystal X-ray diffraction confirmed the proposed molecular structures of both isolated kinetic and thermodynamic products. Complexation with iridium significantly enhances the in vitro activity of selected ligands against the chloroquine-sensitive (NF54) Plasmodium falciparum strain, with selected complexes being over one hundred times more active than their respective ligands. No cross-resistance was observed in the chloroquine-resistant (K1) strain. No cytotoxicity was observed for selected complexes tested against the mammalian Chinese Hamster Ovarian (CHO) cell line. In addition, speed-of-action assays and β-haematin inhibition studies were performed. Through preliminary qualitative and quantitative cell-free experiments, it was found that the two most active neutral, cyclometallated complexes can act as transfer hydrogenation catalysts, by reducing β-nicotinamide adenine dinucleotide (NAD+) to NADH in the presence of a hydrogen source, sodium formate.

Modified Nucleosides, Nucleotides and Nucleic Acids via Click Azide-Alkyne Cycloaddition for Pharmacological Applications

The click azide = alkyne 1,3-dipolar cycloaddition (click chemistry) has become the approach of choice for bioconjugations in medicinal chemistry, providing facile reaction conditions amenable to both small and biological molecules. Many nucleoside analogs are known for their marked impact in cancer therapy and for the treatment of virus diseases and new targeted oligonucleotides have been developed for different purposes. The click chemistry allowing the tolerated union between units with a wide diversity of functional groups represents a robust means of designing new hybrid compounds with an extraordinary diversity of applications. This review provides an overview of the most recent works related to the use of click chemistry methodology in the field of nucleosides, nucleotides and nucleic acids for pharmacological applications.

Antiviral activity of 1,2,4-triazole derivatives (microreview)

The microreview summarizes data published since 2015 on the antiviral properties and synthesis of compounds containing the 1,2,4-triazole ring.

Dextran based amphiphilic self-assembled biopolymeric macromolecule synthesized via RAFT polymerization as indomethacin carrier

This work demonstrates a facile pathway to develop a biopolymer based amphiphilic macromolecule through reversible addition-fragmentation chain transfer (RAFT) polymerization, using dextran (a biopolymer) as starting material. Also, a new hydrophobic monomer [2-methyl-acrylic acid 1-benzyl-1H-[1,2,3] triazol-4-ylmethyl ester (MABTE)] has been synthesized using methacrylic acid via "click" approach. The resultant copolymer displays controlled radical polymerization characteristics: narrow polydispersity (Ð) and controlled molecular weight as obtained through advanced polymer chromatography (APC) analysis. In aqueous solution, the copolymer can proficiently be self-assembled to provide micellar structure, which has been evidenced from field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses. The in-vitro cytotoxicity study illustrates the nontoxic nature of the copolymer up to 100 μg/mL polymer concentration. The copolymer has been found to be worthy as an efficient carrier for the sustained release of hydrophobic drug: Indomethacin (IND).

Evaluation of the high affinity [18F]fluoropyridine-candesartan in rats for PET imaging of renal AT1 receptors

INTRODUCTION

Alterations in the expression of the Angiotensin II type 1 receptors (AT₁R) have been demonstrated in the development of several heart and renal diseases. The aim of this study was to evaluate the novel compound [¹⁸F]fluoropyridine-candesartan as a PET imaging tracer of AT₁R in rat kidneys.

METHODS

Competition binding assays were carried out with membranes from CHO-K1 cells expressing human AT₁R. Binding to plasma proteins was assessed by ultrafiltration. Radiolabeled metabolites in rat plasma and kidneys of control and pretreated animals (candesartan 10 mg/kg or losartan 30 mg/kg) were analyzed by column-switch HPLC. Dynamic PET/CT images of [¹⁸F]fluoropyridine-candesartan in male Sprague-Dawley rats were acquired for 60 min at baseline, pre-treatment with the AT₁R antagonist losartan (30 mg/kg) or the AT₂R antagonist PD123,319 (5 mg/kg).

RESULTS

Fluoropyridine-candesartan bound with a high affinity for AT₁R (Ki = 5.9 ± 1.1 nM), comparable to fluoropyridine-losartan but lower than the parent compound candesartan (Ki = 0.4 ± 0.1 nM). [¹⁸F]Fluoropyridine-candesartan bound strongly to plasma proteins (99.3%) and was mainly metabolized to radiolabeled hydrophilic compounds, displaying minimal interference on renal AT₁R binding with 82% of unchanged tracer in the kidneys at 20 min post-injection. PET imaging displayed high renal and liver accumulations and slow clearances, with maximum tissue-to-blood ratios of 14 ± 3 and 54 ± 12 in kidney cortex and liver, respectively, at 10 min post-injection. Binding specificity for AT₁R was demonstrated with marked reductions in kidney cortex (-84%) and liver (-93%) tissue-to-blood ratios at 20 min post-injection, when blocking with AT₁R antagonist losartan (30 mg/kg). No change was observed in kidney cortex of rats pre-treated with AT₂R antagonist PD 123,319 (5 mg/kg), confirming binding selectivity for AT₁ over AT₂ receptors.

CONCLUSION

High kidney-to-blood ratios and binding selectivity to renal AT₁R combined with tracer in vivo stability displaying minimal interference from labeled metabolites support further PET imaging studies with [¹⁸F]fluoropyridine-candesartan.

Discovery of antiproliferative and anti-FAK inhibitory activity of 1,2,4-triazole derivatives containing acetamido carboxylic acid skeleton

Small molecule inhibitors of the focal adhesion kinase are regarded as promising tools in our armamentarium for treating cancer. Here, we identified four 1,2,4-triazole derivatives that inhibit FAK kinase significantly and evaluated their therapeutic potential. Most tested compounds revealed potent antiproliferative activity in HepG2 and Hep3B liver cancer cells, in which 3c and 3d were the most potent (IC₅₀ range; 2.88 ~ 4.83 µM). Compound 3d possessed significant FAK inhibitory activity with IC₅₀ value of 18.10 nM better than the reference GSK-2256098 (IC₅₀ = 22.14 nM). The preliminary mechanism investigation by Western blot analysis showed that both 3c and 3d repressed FAK phosphorylation comparable to GSK-2256098 in HepG2 cells. As a result of FAK inhibition, 3c and 3d inhibited the pro-survival pathways by decreasing the phosphorylation levels of PI3K, Akt, JNK, and STAT3 proteins. This effect led to apoptosis induction and cell cycle arrest. Taken together, these results indicate that 3d could serve as a potent preclinical candidate for the treatment of cancers.

Design and synthesis of novel quinoline/chalcone/1,2,4-triazole hybrids as potent antiproliferative agent targeting EGFR and BRAFV600E kinases

New quinoline / chalcone hybrids containing 1,2,4-triazole moiety have been designed, synthesized and their structures elucidated and confirmed by various spectroscopic techniques. The designed compounds showed moderate to good activity on different NCI 60 cell lines in a single-dose assay with a growth inhibition rate ranging from 50% to 94%. Compounds 7b, 7d, 9b, and 9d were the most active compounds in most cancer cell lines with a growth inhibition percent between 77% and 94%. Newly synthesized hybrids were evaluated for their anti-proliferative activity against a panel of four human cancer cell lines. Compounds 7a, 7b, 9a, 9b, and 9d showed promising antiproliferative activities. These compounds were further tested for their inhibitory potency against EGFR and BRAF^V600E kinases with erlotinib as a reference drug. The molecular docking study of compounds 7a, 7b, 9a, 9b, and 9d revealed nice fitting into the active site of EGFR and BRAF^V600E kinases. Compounds 7b, 9b, and 9d displayed the highest binding affinities and similar binding pattern to those of erlotinib.

N-substituted benzimidazole acrylonitriles as in vitro tubulin polymerization inhibitors: Synthesis, biological activity and computational analysis

We present the design, synthesis and biological activity of novel N-substituted benzimidazole based acrylonitriles as potential tubulin polymerization inhibitors. Their synthesis was achieved using classical linear organic and microwave assisted techniques, starting from aromatic aldehydes and N-substituted-2-cyanomethylbenzimidazoles. All newly prepared compounds were tested for their antiproliferative activity in vitro on eight human cancer cell lines and one reference non-cancerous assay. N,N-dimethylamino substituted acrylonitriles 30 and 41, bearing N-isobutyl and cyano substituents placed on the benzimidazole nuclei, showed strong and selective antiproliferative activity in the submicromolar range of inhibitory concentrations (IC₅₀ 0.2-0.6 μM), while being significantly less toxic than reference systems docetaxel and staurosporine, thus promoting them as lead compounds. Mechanism of action studies demonstrated that two most active compounds inhibited tubulin polymerization. Computational analysis confirmed the suitability of the employed benzimidazole-acrylonitrile skeleton for the binding within the colchicine binding site in tubulin, thus rationalizing the observed antitumor activities, and demonstrated that E-isomers are active substances. It also provided structural determinants affecting both the binding position and the matching affinities, identifying the attached NMe₂ group as the most dominant in promoting the binding, which allows ligands to optimize favourable cation∙∙∙π and hydrogen bonding interactions with Lys352.