Search Results (87)

Microtubules play a key role in cell division and cell migration. Thus, microtubule-targeting agents (MTAs) are pivotal in cancer therapy due to their ability to disrupt cell division microtubule dynamics. Traditionally divided into stabilizers and destabilizers, MTAs are increasingly being repurposed for central nervous system (CNS) applications, including brain malignancies such as gliomas and neurodegenerative diseases like Alzheimer’s and Parkinson’s. Microtubule-stabilizing agents, such as taxanes and epothilones, promote microtubule assembly and have shown efficacy in both tumour suppression and neuronal repair, though their CNS use is hindered by blood–brain barrier (BBB) permeability and neurotoxicity. Destabilizing agents, including colchicine-site and vinca domain binders, offer potent anticancer effects but pose greater risks for neuronal toxicity. This review highlights the mapping of nine distinct tubulin binding pockets—including classical (taxane, vinca, colchicine) and emerging (tumabulin, pironetin) sites—that offer new pharmacological entry points. We summarize the recent advances in structural biology and drug design, enabling MTAs to move beyond anti-mitotic roles, unlocking applications in both cancer and neurodegeneration for next-generation MTAs with enhanced specificity and BBB penetration. We further discuss the therapeutic potential of combination strategies, including MTAs with radiation, histone deacetylase (HDAC) inhibitors, or antibody–drug conjugates, that show synergistic effects in glioblastoma models. Furthermore, innovative delivery systems like nanoparticles and liposomes are enhancing CNS drug delivery. Overall, MTAs continue to evolve as multifunctional tools with expanding applications across oncology and neurology, with future therapies focusing on optimizing efficacy, reducing toxicity, and overcoming therapeutic resistance in brain-related diseases. Full article

Mammary tumors are the most common neoplasms diagnosed in female dogs and have been considered excellent models for studying human breast cancer. Establishing cell lines from primary cultures of canine mammary tumors provides an in vitro model to better understand the disease and develop new treatments. This study aimed to establish and characterize canine mammary tumor cell lines. Ten cell cultures were generated from tumor tissue obtained from affected dogs, including seven from primary mammary tumors and three from metastatic sites. Characterization included molecular marker expression (ER, PR, HER2, cytokeratin 5/6 (CK5/6), vimentin, and the marker of cell proliferation Ki67) and in vitro tumorigenic capacity assessment. Additionally, the susceptibility of five cell lines to DOX, 5-FU, paclitaxel, colchicine, and carboplatin was evaluated using the MTT assay. ICC analysis revealed negative expression of hormonal receptors (ER and PR) in five cell lines, while only one cell line was positive for both. Six cell lines were HER2-negative and positive for vimentin. Five cell lines exhibited in vitro tumorigenic capacity, forming colonies in soft agar. DOX showed the highest growth-inhibitory effect (DOX > Paclitaxel > Colchicine > 5-FU > Carboplatin). Two cell lines had a minimal concentration for 50% inhibition in vitro (IC₅₀) < 0.63 µM and 4.37 ± 0.40 µM for DOX, while one was sensitive to colchicine and paclitaxel (IC₅₀ 0.19 µM and 0.04 µM, respectively). All tested cell lines were resistant to carboplatin and 5-FU. These cell lines provide a valuable model for studying breast cancer in humans and dogs and evaluating new potential therapeutic strategies. Full article

Background: Parasitic worm infections remain among the most prevalent and neglected health issues worldwide, affecting both humans and animals. Toxocariasis, caused by Toxocara spp., is a widespread zoonosis with significant public health and economic implications. Current anthelmintic treatments show limited efficacy, particularly against tissue-migrating larvae, underscoring the urgent need for new therapeutic options. This study aimed to evaluate the anthelmintic potential of H₁ antihistamines as repurposed drug candidates against Toxocara canis. Methods: Twenty-two H₁ antihistamines were screened for larvicidal activity against infective third-stage (L3) larvae of T. canis. Larval motility and morphology were assessed, and compounds with the highest efficacy were further investigated using density functional theory (DFT) to explore their electronic properties. Molecular docking simulations were also performed to predict interactions with T. canis β-tubulin. Results: Promethazine and rupatadine exhibited significant larvicidal effects, surpassing albendazole in reducing larval motility and inducing a distinct contorted morphology not observed in control or albendazole-treated larvae. DFT analyses suggested a strong electron-acceptor capacity, indicating a potential redox-based mechanism of action. Docking studies revealed favorable binding to the colchicine site of T. canis β-tubulin. Conclusions: This is the first report of larvicidal activity of antihistamines against T. canis, supporting their potential as repurposed therapeutic agents for the treatment of zoonotic helminthiases, particularly those caused by tissue-migrating nematodes. Full article

High-risk neuroblastoma remains a clinically challenging pediatric cancer, with an approximate five-year survival rate of ~60%. Frontline therapy for this group of patients includes surgery and intensive chemotherapy that involves combinations of the tubulin inhibitor vincristine with several other chemotherapeutics. Unfortunately, unresponsiveness to therapy and relapse are common, with tumors often displaying resistance to vincristine. Recently, we characterized a novel set of tubulin inhibitors that are distinct from vincristine and bind within the colchicine binding site present on tubulin monomers. Colchicine binding site inhibitors (CBSIs) have gained traction as improved chemotherapeutics due to their potential to overcome tubulin inhibitor-induced resistance. In this study, we investigate the functional impact of CBSI treatment on multiple neuroblastoma cell lines, including those that are vincristine-resistant. We demonstrate that our newly developed compounds are effective at disrupting cell division in non-resistant and resistant cells and have cellular activity against vincristine-resistant cell lines. Interestingly, we find that vincristine-resistant cell lines differ in their ability to undergo apoptotic cell death in response to CBSI treatment. Taken together, these findings provide a solid foundation to further investigate the utility of CBSIs for neuroblastoma treatment, while highlighting the distinct resistance mechanisms that can emerge in these childhood cancers. Full article

Background/Objectives: The synthesis of (E)-1-(1,3-diphenylallyl)-1H-1,2,4-triazoles and related compounds as anti-mitotic agents with activity in breast cancer was investigated. These compounds were designed as hybrids of the microtubule-targeting chalcones, indanones, and the aromatase inhibitor letrozole. Methods: A panel of 29 compounds was synthesized and examined by a preliminary screening in estrogen receptor (ER) and progesterone receptor (PR)-positive MCF-7 breast cancer cells together with cell cycle analysis and tubulin polymerization inhibition. Results: (E)-5-(3-(1H-1,2,4-triazol-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-1-en-1-yl)-2-methoxyphenol 22b was identified as a potent antiproliferative compound with an IC₅₀ value of 0.39 mM in MCF-7 breast cancer cells, 0.77 mM in triple-negative MDA-MB-231 breast cancer cells, and 0.37 mM in leukemia HL-60 cells. In addition, compound 22b demonstrated potent activity in the sub-micromolar range against the NCI 60 cancer cell line panel including prostate, melanoma, colon, leukemia, and non-small cell lung cancers. G₂/M phase cell cycle arrest and the induction of apoptosis in MCF-7 cells together with inhibition of tubulin polymerization were demonstrated. Immunofluorescence studies confirmed that compound 22b targeted tubulin in MCF-7 cells, while computational docking studies predicted binding conformations for 22b in the colchicine binding site of tubulin. Compound 22b also selectively inhibited aromatase. Conclusions: Based on the results obtained, these novel compounds are suitable candidates for further investigation as antiproliferative microtubule-targeting agents for breast cancer. Full article

Gastrointestinal nematodes (GINs) inflict significant economic losses on sheep and goat farming globally due to reduced productivity and the development of anthelmintic resistance. Sustainable control strategies are urgently needed including the exploration of medicinal plants as safer alternatives to chemical anthelmintics. This genus of plants is used for anti-inflammatory, antioxidant, and antimicrobial activities. In this study, we aimed to evaluate the anthelmintic activities of Nepeta racemosa Lam. MeOH extract, n-hexane, dichloromethane (DCM), ethyl acetate (EtOAc), n-buthanol (n-BuOH) and aqueous (H₂O) subextracts, and quantify rosmarinic acid in the active extract by the HPLC method, and perform in silico molecular docking studies of rosmarinic acid to examine its binding interactions with tubulin. The anthelmintic activity of the plant extracts on gastrointestinal nematode eggs and larvae (L3) of the sheep was assessed using in vitro test methods such as the egg hatch assay and larval motility assay, conducted over a 24 h period (1, 2, 3, 4, 6, 8, 24). All extracts exhibited 100% effectiveness in the egg hatch inhibition assay, regardless of concentration (50–1.5625 mg/mL). The EtOAc subextract shows the highest effectiveness at 79.66%, followed by the MeOH extract at 74.00%, water at 64.00%, n-hexane at 67.00%, and DCM at 61.00%, and the lowest effectiveness is observed with n-BuOH at 51.66% in the larval motility assay. The major compound of EtOAc extract, the most active extract of N. racemosa, was determined as rosmarinic acid and its amount in the extract was determined as 14.50 mg/100 mg dry extract. The amount of rosmarinic acid in the MeOH extract was found to be 0.21 mg/100 mg dry extract. n-Hexane, DCM, n-BuOH, and H₂O extracts’ rosmarinic acid content was lower than the LOQ value. As tubulin plays an important role in the mechanism of anthelmintics, the major compound of the most active extract (NR-EtOAc) rosmarinic acid was docked onto the colchicine-binding site of the tubulin (5OV7) protein. Rosmarinic acid showed a similar activity spectrum to the anthelmintic drug albendazole. The discovery of low-cost and low-toxicity anthelmintic compounds is very important. Full article

The natural products combretastatins A-1 and A-4 are potent antimitotic and vascular-disrupting agents through their binding at the colchicine site in tubulin. However, these compounds suffer from a low water solubility and a tendency to isomerize to the inactive trans stilbenes. In this study, we have prepared a series of 18 cis-restricted triazole analogues of combretastatin A-4 (CA-4), maintaining, in all cases, the 3,4,5-trimethoxy phenyl ring A, with the aim of investigating the substitution pattern on the B-ring in a systematic way. To this end, cytotoxic activities of the cis-restricted analogues of CA-4 prepared were determined in two tumor cell lines, namely, HT-29 and A-549, as well as in the non-tumor cell line HEK-293, to pre-evaluate the selectivity profile of the compounds for the tumor cell lines. The main conclusion was the essential presence of methoxyl or ethoxyl groups at the para position of the B-ring in order to obtain good antitumor activities. Thus, the more active compounds in our study displayed IC₅₀ values in the nanomolar range for the tumor cell lines but not for the normal cells. Consequently, these triazole analogues of CA-4 could serve as promising alternatives to the natural product, although further studies about their biological activity are essential in order to fully determine their viability as therapeutic agents in the treatment of cancer. Full article

Skin diseases are a common health problem affecting millions of people worldwide. Effective treatment often depends on the precise delivery of drugs to the affected areas. One promising approach is currently the transdermal drug delivery system (TDDS), whose significant challenge is the poor penetration of many compounds into the skin due to the stratum corneum (SC), which acts as a formidable barrier. To overcome this limitation, nanocarriers have emerged as a highly effective alternative. This review discusses the use of liposomes and ethosomes for transdermal drug delivery. Liposomes are micro- or nanostructures consisting of a lipid bilayer surrounding an aqueous core. They facilitate transdermal drug penetration and may be advantageous for site-specific targeting. Some methods of treating skin diseases involve incorporating drugs such as acyclovir, dithranol, and tretinoin or bioactive compounds such as fluconazole, melanin, glycolic acid, kojic acid, and CoQ10 into nanocarriers. The inability of liposomes to pass through the narrowed intercellular channels of the stratum corneum led to the invention of lipid-based vesicular systems such as ethosomes. They are structurally similar to conventional liposomes, as they are prepared from phospholipids, but they contain a high ethanol concentration. Ethosomes are noninvasive carriers that allow drugs to reach the deep layers of the skin. Examples of commonly used substances and drugs combined with ethosomes in cosmetics include methotrexate, ascorbic acid, vitamin A and E, and colchicine. A significant development in this area is the use of rutin-loaded ethosomes. Encapsulating rutin in ethosomes significantly improves its stability and enhances skin penetration, allowing more efficient delivery to deeper skin layers. In cosmetics, rutin–ethosome formulations are used to protect the skin from oxidative stress, reduce redness, and improve capillary strength, making it a valuable formulation in anti-aging and anti-inflammatory products. The results of the first clinical trial of the acyclovir–ethosome formulation confirm that ethosomes require further investigation. The work provides an update on recent advances in pharmaceutical and cosmetic applications, mentioning the essential points of commercially available formulations, clinical trials, and patents in the recent past. Full article

A series of novel thiazole-based chalcones were evaluated for their anticancer activity as potential tubulin polymerization inhibitors. In vitro anticancer screening for the thiazole derivatives 2a–2p exhibited broad-spectrum antitumor activity against various cancer cell lines particularly Ovar-3 and MDA-MB-468 cells with a GI₅₀ range from 1.55 to 2.95 μΜ, respectively. Compound 2e demonstrated significant inhibition of tubulin polymerization, with an IC₅₀ value of 7.78 μM compared to Combretastatin-A4 (CA-4), with an IC₅₀ value of 4.93 μM. Molecular docking studies of compounds 2e, 2g, and 2h into tubulin further supported these findings, revealing that they bind effectively to the colchicine binding site, mirroring key interactions exhibited by CA-4. Computational predictions suggested favorable oral bioavailability and drug-likeness for these compounds, highlighting their potential for further development as chemotherapeutic agents. Full article

Combretastatins isolated from the Combretum caffrum tree belong to a group of closely related stilbenes. They are colchicine binding site inhibitors which disrupt the polymerization process of microtubules in tubulins, causing mitotic arrest. In vitro and in vivo studies have proven that some combretastatins exhibit antitumor properties, and among them, combretastatin A-4 is the most active mitotic inhibitor. In this study, a series of novel combretastatin A-4 analogs containing carboxylic acid, ester, and amide moieties were synthesized and their cytotoxic activity against six tumor cell lines was determined using sulforhodamine B assay. For the most cytotoxic compounds (8 and 20), further studies were performed. These compounds were shown to induce G0/G1 cell cycle arrest in MDA and A549 cells, in a concentration-dependent manner. Moreover, in vitro tubulin polymerization assays showed that both compounds are tubulin polymerization enhancers. Additionally, computational analysis of the binding modes and binding energies of the compounds with respect to the key human tubulin isotypes was performed. We have obtained a satisfactory correlation of the binding energies with the IC₅₀ values when weighted averages of the binding energies accounting for the abundance of tubulin isotypes in specific cancer cell lines were computed. Full article

The clinical application of 2-methoxyestradiol (2ME) in cancer therapy has been limited by its low solubility and rapid metabolism. Derivatives of 2ME have been synthesised to enhance bioavailability and decrease hepatic metabolism. Compound 4a, an analog of 2ME, has demonstrated exceptional pharmacological activity, in addition to promising pharmacokinetic profile. Our study, therefore, aimed at exploring the anticancer effects of 4a on the cervical cancer cell line, HeLa. Compound 4a exhibited a significant and dose-dependent antimetastatic and antiinvasive impact on HeLa cells, as determined by wound-healing and Boyden chamber assays, respectively. Hoechst/Propidium iodide (HOPI) double staining showcased a substantial induction of apoptosis via 4a, with minimal necrotic effect. Flow cytometry revealed a significant G2/M phase arrest, accompanied by a noteworthy rise in the sub-G1 cell population, indicating apoptosis, 18 h post-treatment. Moreover, a cell-independent tubulin polymerisation assay illustrated compound 4a’s ability to stabilise microtubules by promoting tubulin polymerisation. Molecular modelling experiments depicted that 4a interacts with the colchicine-binding site, nestled between the α and β tubulin dimers. Furthermore, 4a displayed an affinity for binding to and activating ER-α, as demonstrated by the luciferase reporter assay. These findings underscore the potential of 4a in inhibiting HPV18+ cervical cancer proliferation and cellular motility. Full article

Glioblastoma (GB) is the most lethal brain cancer in adults, with a 5-year survival rate of 5%. The standard of care for GB includes maximally safe surgical resection, radiation, and temozolomide (TMZ) therapy, but tumor recurrence is inevitable in most GB patients. Here, we describe the development of a blood–brain barrier (BBB)-penetrant tubulin destabilizer, RGN3067, for the treatment of GB. RGN3067 shows good oral bioavailability and achieves high concentrations in rodent brains after oral dosing (C_max of 7807 ng/mL (20 μM), T_max at 2 h). RGN3067 binds the colchicine binding site of tubulin and inhibits tubulin polymerization. The compound also suppresses the proliferation of the GB cell lines U87 and LN-18, with IC₅₀s of 117 and 560 nM, respectively. In four patient-derived GB cell lines, the IC₅₀ values for RGN3067 range from 148 to 616 nM. Finally, in a patient-derived xenograft (PDX) mouse model, RGN3067 reduces the rate of tumor growth compared to the control. Collectively, we show that RGN3067 is a BBB-penetrant small molecule that shows in vitro and in vivo efficacy and that its design addresses many of the physicochemical properties that prevent the use of microtubule destabilizers as treatments for GB and other brain cancers. Full article

Antimitotic agents are one of the more successful types of anticancer drugs, but they suffer from toxicity and resistance. The application of approved drugs to new indications (i.e., drug repurposing) is a promising strategy for the development of new drugs. It relies on finding pattern similarities: drug effects to other drugs or conditions, similar toxicities, or structural similarity. Here, we recursively searched a database of approved drugs for structural similarity to several antimitotic agents binding to a specific site of tubulin, with the expectation of finding structures that could fit in it. These searches repeatedly retrieved frentizole, an approved nontoxic anti-inflammatory drug, thus indicating that it might behave as an antimitotic drug devoid of the undesired toxic effects. We also show that the usual repurposing approach to searching for targets of frentizole failed in most cases to find such a relationship. We synthesized frentizole and a series of analogs to assay them as antimitotic agents and found antiproliferative activity against HeLa tumor cells, inhibition of microtubule formation within cells, and arrest at the G₂/M phases of the cell cycle, phenotypes that agree with binding to tubulin as the mechanism of action. The docking studies suggest binding at the colchicine site in different modes. These results support the repurposing of frentizole for cancer treatment, especially for glioblastoma. Full article

Tubulin-targeting agents attract undiminished attention as promising compounds for the design of anti-cancer drugs. Verubulin is a potent tubulin polymerization inhibitor, binding to colchicine-binding sites. In the present work, a series of verubulin analogues containing a cyclohexane or cycloheptane ring 1,2-annulated with pyrimidine moiety and various substituents in positions 2 and 4 of pyrimidine were obtained and their cytotoxicity towards cancer and non-cancerous cell lines was estimated. The investigated compounds revealed activity against various cancer cell lines with IC₅₀ down to 1–4 nM. According to fluorescent microscopy data, compounds that showed cytotoxicity in the MTT test disrupt the normal cytoskeleton of the cell in a pattern similar to that for combretastatin A-4. The hit compound (N-(4-methoxyphenyl)-N,2-dimethyl-5,6,7,8-tetrahydroquinazolin-4-amine) was encapsulated in biocompatible nanocontainers based on Ca²⁺ or Mg²⁺ cross-linked alginate and it was demonstrated that its cytotoxic activity was preserved after encapsulation. Full article

A series of novel 3-(prop-1-en-2-yl)azetidin-2-one, 3-allylazetidin-2-one and 3-(buta-1,3-dien-1-yl)azetidin-2-one analogues of combretastatin A-4 (CA-4) were designed and synthesised as colchicine-binding site inhibitors (CBSI) in which the ethylene bridge of CA-4 was replaced with a β-lactam (2-azetidinone) scaffold. These compounds, together with related prodrugs, were evaluated for their antiproliferative activity, cell cycle effects and ability to inhibit tubulin assembly. The compounds demonstrated significant in vitro antiproliferative activities in MCF-7 breast cancer cells, particularly for compounds 9h, 9q, 9r, 10p, 10r and 11h, with IC₅₀ values in the range 10–33 nM. These compounds were also potent in the triple-negative breast cancer (TBNC) cell line MDA-MB-231, with IC₅₀ values in the range 23–33 nM, and were comparable with the activity of CA-4. The compounds inhibited the polymerisation of tubulin in vitro, with significant reduction in tubulin polymerization, and were shown to interact at the colchicine-binding site on tubulin. Flow cytometry demonstrated that compound 9q arrested MCF-7 cells in the G₂/M phase and resulted in cellular apoptosis. The antimitotic properties of 9q in MCF-7 human breast cancer cells were also evaluated, and the effect on the organization of microtubules in the cells after treatment with compound 9q was observed using confocal microscopy. The immunofluorescence results confirm that β-lactam 9q is targeting tubulin and resulted in mitotic catastrophe in MCF-7 cells. In silico molecular docking supports the hypothesis that the compounds interact with the colchicine-binding domain of tubulin. Compound 9q is a novel potent microtubule-destabilising agent with potential as a promising lead compound for the development of new antitumour agents. Full article