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C-13 reduced the polymeric/soluble tubulin fraction in HeLa cells as determined by western blot. (A) HeLa cells were treated either without or with 120 and 240 nM C-13 for 24 h. Vinblastine (25 nM) was used as a positive control. The polymeric and soluble fractions of tubulin were isolated and an equal amount of protein was loaded onto sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoblotting was carried out using a monoclonal antibody against ?-tubulin. The experiment was carried out three times. One of the blots is shown. (B) Ratio of polymer/soluble tubulin fraction was quantified using ImageJ software, and statistical significance was determined using student's t-test. (ns: p > 0.05; *: p < 0.05). The error bar signifies standard deviation.
Source publication
Combretastatin (CA-4) and its analogues are undergoing several clinical trials for treating different types of tumors. In this work, the antiproliferative activity of a series of 2-aminoimidazole-carbonyl analogs of clinically relevant combretastatins A-4 (CA-4) and A-1 was evaluated using a cell-based assay. Among the compounds tested, C-13 and C-...
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... finding indicated that C-13 exerted 15.7 and 4 times stronger antiproliferative effects on MCF-7 breast cancer cells and B16F10 skin melanoma cells than noncancerous MCF 10A breast epithelial cells and L929 skin fibroblast cells, respectively. CA-4 inhibited the proliferation of MCF-7 and MCF 10A cells with an IC 50 of 18 ± 3 and 144 ± 31 nM, respectively ( Figure S6). The antiproliferative activity of C-21 was also tested in B16F10 and L929 cells. ...
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... confirm that C-13 induced microtubule depolymeriza- tion in HeLa cells, the ratio of polymeric to soluble tubulin in HeLa cells was determined using western blotting ( Figure 6A). The ratio of polymeric to soluble tubulin in HeLa cells was determined to be 2.1 ± 0.4, 1.6 ± 0.1, and 1.1 ± 0.1 in the absence and presence of 120 and 240 nM C-13 ( Figure 6B). ...
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... confirm that C-13 induced microtubule depolymeriza- tion in HeLa cells, the ratio of polymeric to soluble tubulin in HeLa cells was determined using western blotting ( Figure 6A). The ratio of polymeric to soluble tubulin in HeLa cells was determined to be 2.1 ± 0.4, 1.6 ± 0.1, and 1.1 ± 0.1 in the absence and presence of 120 and 240 nM C-13 ( Figure 6B). The ratio of polymeric to soluble tubulin of cells treated with 25 nM vinblastine was found to be 1.4 ± 0.9. ...
Citations
... Недостатком СА-4 и СА-1 является также их способность в белковых средах изомеризоваться по олефиновой двойной связи из активной цитотоксической cis-конформации в соответствующую trans-неактивную форму, что значительно снижает их ценность в качестве активного компонента противоопухолевого препарата и накладывает существенные ограничения на их клиническое применение. Вместе с тем разнообразные подходы, включающие получение пролекарств, солей, структурных модификаций, предотвращение конверсии олефиновой двойной связи и включение заместителей в ароматические кольца молекул, привели к успешному синтезу многих аналогов и производных комбретастатинов, прежде всего СА-4, которые проявляют активность в отношении различных типов опухолевых клеток и ксенографтов в исследованиях in vitro и in vivo [21,[26][27][28][29]. ...
... As part of our research on natural product-based anticancer drug discovery, we previously discovered CA-4-inspired several new heterocyclic molecules ( Figure 2). While retaining essential pharmacophoric features of CA-4, its double bond was replaced with biologically important different heterocyclic motifs, including an imidazopyridine-NH bridge, [17] a 2-aminoimidazole heterocyclic motif, [18] a 2-aminoimidazole-carbonyl bridge [19] and a functional N-heterocyclic motif present in a drug molecule Celecoxib that is known to possess significant anticancer property. [20] Our investigations led to important findings of molecular aspects and biological properties, including 1) double bond-alternative unique bridging motifs, 2) previously unknown heterocycle as ring B, and 3) anticancer activities and interactions with tubulin. ...
... Compound 16 induced the G2/M block and resulted in the formation of multiple nuclei in MCF-7 cells, leading to cell death after two cell cycles. In the investigated title class of compounds, numerous unique pharmacophoric features important for colchicine-binding, tubulin polymerization inhibition, ChemMedChem 2024, 19, e202300562 (8 of 10) and cell cycle arrest leading to antiproliferation of cancer cells have been identified. The present study has potential in medicinal chemistry research in terms of design strategy, structure-function characteristics for tubulin-binding and antiproliferative properties, and identified new potent anticancer compounds. ...
An approach of natural product‐inspired strategy and incorporation of an NP‐privileged motif has been investigated for the discovery of new tubulin polymerization inhibitors. Two series, N‐Arylsulfonyl‐3‐arylamino‐5‐amino‐1,2,4‐triazole derivatives, and their isomers were considered. The compounds were synthesized by construction of the N‐aryl‐1,2,4‐triazole‐3,5‐diamine motif and sulfonylation. Although the chemo‐ and regioselectivity in sulfonylation were challenging due to multiple ring‐tautomerizable‐NH and exocyclic NH2 functionalities present in the molecular motifs, the developed synthetic method enabled the preparation of designed molecular skeletons with biologically important motifs. The approach also led to explore interesting molecular regio‐ and stereochemical aspects valuable for activity. The X‐ray crystallography study indicated that the hydrogen bonding between the arylamine‐NH and the arylsulfonyl‐“O” unit and appropriate molecular‐functionality topology allowed the cis‐locking of two aryls, which is important for tubulin‐binding and antiproliferative properties. All synthesized compounds majorly showed characteristic antiproliferative effects in breast cancer cells (MCF‐7), and four compounds exhibited potent antiproliferative activity. One compound potently bound to tubulin at the colchicine site and inhibited tubulin polymerization in vitro. The compound significantly depolymerized microtubules in MCF‐7 cells, arrested the cells at the G2/M phase, and induced cell death. This study represents the importance of the design strategy in medicinal chemistry and the molecular structural features relevant to anticancer anti‐tubulin properties. The explored molecules have the potential for further development.
... Combretastatin (Chart 36) is dynamic against colon, lung, and leukemia malignant growths and, normally, this atom is the most cytotoxic phyto molecule (Hura, 2018). Rhizomes of A. officinarum, A. zerumbet, and A. calcarata include a high iron level as well as a moderate and balanced carbohydrate, protein, fat, and crude fiber content. ...
This review study investigates conventional anticancer treatments derived from the world's different parts as a wonderful substitute for pharmaceuticals since they have fewer or no side effects and can fix the disease at its source. This study provides thorough information regarding physiologically active substances derived from various parts of the plant for cancer treatment such as Alkaloids (ervine, methylervine, ervolanine, and aervolanine), Terpenoids, Vitamins, Coumarins, Tannins, Carbohydrates, Flavonoids (kaempferol, quercetin, isorhamnetin, persinol, persinosides A and B), Fatty Acids, and Essential Oils). This technique is beneficial in clinical studies for breast, prostate, and colon cancer. The ongoing rise in cancer incidence, the inability of traditional chemotherapies to manage cancer, and the excessive toxicity of chemotherapies all call for a new strategy. The first trial to establish the effectiveness of chemoprevention was conducted in breast cancer patients using tamoxifen, which indicated a substantial reduction in invasive breast cancer. The effectiveness of utilizing chemopreventive drugs to protect high-risk people from cancer suggests that the technique is sound and promising. Dietary components such as capsaicin, cucurbitacin B, isoflavones, catechins, lycopene, benzyl isothiocyanate, phenethyl isothiocyanate, and piperlongumine have been shown to suppress cancer cell growth, indicating that they might be used as chemopreventive agents.
... In this frame, among the inhibitors of tubulin polymerization, there is CA4 (Fig. 7), an antimitotic, antiproliferative and antiangiogenic agent [134][135][136][137][138][139]. Indeed, by binding to the β-subunit of tubulin, CA4 prevents the cell's production of microtubules, which are crucial for cytoskeleton formation [140,141]. ...
The discovery of the antineoplastic properties of cisplatin in 1965 by Rosenberg and co-workers, originated a renewed attraction for metal complexes for medicinal applications. Indeed, after its first outstanding clinical results, chemists involved in the metal
complexes research field readily started to study safer and more effective alternatives to cisplatin itself. In this frame, after decades of intensive research mainly focused on classical Pt(II) compounds, also platinum(IV)-based compounds have been taken into account. The reason for this interest is that, despite the kinetic inertness of Pt(IV) compounds, they can undergo to “in-cell” reduction process which is able to activate the platinum centre through the generation of the more reactive Pt(II) counterpart. This kind of approach might offer some relevant advantages, such as the reduction of severe side effects associated with Pt(II) off-target reactions. Indeed, the lower redox potential of cancer cells with respect to the healthy ones is able to trigger the Pt(IV) reduction into the biologically active counterpart. In this review, we summarized the most recent goals achieved in the field of so-called Pt(IV) prodrugs.
... Copper-based complexes trigger the production of ROS, causing a decrease in cell viability; 8 we therefore investigated if Cu-PLN triggered ROS production using DCFDA dye. 32,33 Cu-PLN treatment significantly increased the percentage of ROS-positive cells, as observed by an increase in DCFDA fluorescence ( Figure 11). Incubation of HeLa cells with 1 and 2 μM Cu-PLN for 2, 4, and 24 h led to a time-dependent increase in the percentage of ROS-positive cells ( Figure 11A− C). ...
Here, we have synthesized a copper complex of plumbagin (Cu-PLN) and investigated its antiproliferative activities in different cancer cells. The crystal structure of Cu-PLN showed that the complex was square planar with a binding stoichiometry of 1:2 (Cu/Plumbagin). Cu-PLN inhibited the proliferation of human cervical carcinoma (HeLa), human breast cancer (MCF-7), and murine melanoma (B16F10) cells with half-maximal inhibitory concentrations (IC50) of 0.85 ± 0.05, 2.3 ± 0.1, and 1.1 ± 0.1 μM, respectively. Plumbagin inhibited the proliferation of HeLa, MCF-7, and B16F10 cells with IC50 of 7 ± 0.1, 8.2 ± 0.2, and 6.2 ± 0.4 μM, respectively, showing that Cu-PLN is a stronger antiproliferative agent than plumbagin. Interestingly, Cu-PLN showed much stronger toxicity against breast carcinoma and skin melanoma cells than noncancerous breast epithelial and skin fibroblast cells, indicating its specific cytotoxicity toward cancer cells. A short exposure of Cu-PLN triggered microtubule disassembly in cultured cancer cells, and the complex also inhibited the polymerization of purified tubulin much more strongly than plumbagin. Furthermore, Cu-PLN inhibited the binding of colchicine to tubulin. In addition to microtubule depolymerization, the antiproliferative mechanism of Cu-PLN involved induction of reactive oxygen species, reduction of the mitochondrial membrane potential, and DNA damage. Moreover, the cytotoxic effects of Cu-PLN reduced significantly in cells pre-treated with N-acetyl cysteine, suggesting that reactive oxygen species generation is crucial in Cu-PLN's mode of action. Thus, the complexation of plumbagin with copper yields a promising antitumor agent having a stronger antiproliferative activity than cisplatin, a widely used anticancer drug.
... An intriguing approach for discovering CA4 related tubulin inhibitors was recently reported, with the assembly of 2-aminoimidazolecarbonyl as a bridging motif, trimethoxyphenyl as a ring, and different aryls and heteroaryls as the other ring [64]. The insertion of a carbonylic moiety was found to inhibit the tubulin assembly and enhance the antiproliferative effects. ...
Medicinal chemists around the world have been inspired by nature and have successfully extracted chemicals from plants. Research on enzymatic modifications of naturally occurring compounds has played a critical role in the search for biologically active molecules to treat diseases. This book explores compounds of interest to researchers and clinicians. It presents a comprehensive analysis about the medicinal chemistry (drug design, structure-activity relationships, permeability data, cytotoxicity, appropriate statistical procedures, and molecular modeling studies) of different compounds. Each chapter brings contributions from known scientists explaining experimental results which can be translated into clinical practice. Each chapter follows a specific format for a phytochemical agent with common chemical features: General background on the (phyto)chemistry of the scaffold General background on the pharmacological profile of the scaffold A Description of the proposed derivatives and their advantages with respect to the parent compounds (emphasizing the synthetic approaches and structure-activity relationships) In silico analysis of the crucial interactions with the biological target Clinical studies and patent survey (if available) on the new and proposed structures The objective of this book set is to fulfil gaps in currently acquired knowledge with information from the recent years. It serves as a guide for academic and professional researchers and clinicians.
... On the account of pharmacophore character of 2-AI unit, numerous synthetic variants have been formed in the last decades highlighting the preparation of C-4/C-5 substituted 2-AI analogues (Nagasawa & Hashimoto, 2003;Weinreb, 2007). Depending on the substitution pattern, significant antimicrobial activity (against Gram-positive bacteria, Escherichia coli and/or Candida albicans) (Figure 1a), antiproliferative effects F I G U R E 1 Naturally occurring marine sponge alkaloids (Oroidin, Clathrodin, Hymenin, and Naamines) and their synthetic descendants focusing on their structural modification at carbon 4 and/or 5 position have been achieved (Chaudhary et al., 2016;Chong et al., 2012;Dyson et al., 2014;Hura et al., 2018;Su et al., 2012;Tomašič et al., 2015;Zidar et al., 2014). ...
Here, we describe the synthesis and biologic activity evaluation of 20 novel synthetic marine sponge alkaloid analogues with 2‐amino‐1H‐imidazol (2‐AI) core. Cytotoxicity was tested on murine 4T1 breast cancer, A549 human lung cancer, and HL‐60 human myeloid leukemia cells by the resazurin assay. A total of 18 of 20 compounds showed cytotoxic effect on the cancer cell lines with different potential. Viability of healthy human fibroblasts and peripheral blood mononuclear cells upon treatment was less hampered compared to cancer cell lines supporting tumor cell specific cytotoxicity of our compounds. The most cytotoxic compounds resulted the following IC50 values 28: 2.91 µM on HL‐60 cells, and 29: 3.1 µM on 4T1 cells. The A549 cells were less sensitive to the treatments with IC50 15 µM for both 28 and 29. Flow cytometry demonstrated the apoptotic effect of the most active seven compounds inducing phosphatidylserine exposure and sub‐G1 fragmentation of nuclear DNA. Cell cycle arrest was also observed. Four compounds caused depolarization of the mitochondrial membrane potential as an early event of apoptosis. Two lead compounds inhibited tumor growth in vivo in the 4T1 triple negative breast cancer and A549 human lung adenocarcinoma xenograft models. Novel marine sponge alkaloid analogues are demonstrated as potential anticancer agents for further development.
... On the contrary, nRCOOH has a negative contribution to the biological activity, this is due to its high polarity, complicating the crossing through hydrophobic biological barriers. In the case of nArC ¼ N, its negative contribution is associated with the steric effect of these groups, which are present in a molecular fragment in many compounds (79)(80)(81)(82)(83)(84)(85)(86)(87)(88)(89)(90)(91)(92)(93)(94)(95). This fragment is dibenzopyrrole, a three-ring heterocyclic system, which we can associate to steric and shape problems of the molecules that have them. ...
... [90,91] Some natural products of this type, characterized by inhibiting tubulin polymerization ( Figure 15SA-15SD), are colchicine, podophyllotoxin, steganacin, and Combretastatin A4 (CA-4). [92][93][94] While structure-activity relationship studies have shown that the colchicine binding site Research Article www.molinf.com inhibitor (CBSI) compounds of CA-4 type are constituted of a diaryl system (Rings A and B) joined through a double bond. ...
Cervical cancer is one of the most aggressive and important cancers in the female population, gith a low survival rate. The search for new bioactive compounds, through the generation of derivatives of known compounds, like gallic and cinnamic acid, has been a successful strategy in antineoplastics area. In the present study, 134 phenolic compounds with cytotoxic activity over HeLa cell line were used to generate a descriptive (R^2=0.76) and predictive (Q^2=0.69 and Q_ext^2=0.62) QSAR model. Structural, electronic, steric, and hydrophobic features are represented as different molecular descriptors in our QSAR model. From this model, nine gallate‐cinnamate ester derivatives (N1‐N9) were designed and synthesized. Furthermore, in vitro cytotoxic activity was evaluated against HeLa and non‐tumorigenic cells. Derivatives N6, N5, N1, and N9 were the most active molecules with IC50ExpHeLa values from 7.26 to 11.95 µM. Finally, the binding of the synthesized compounds to the colchicine binding site on tubulin was evaluated by molecular docking as a possible action mechanism. N1, N5 and N6 can be considered as templates for the design of new cervical anticancer compounds.
... Combretastatin A-4 (CA-4) ( I , Fig. 1 ) is a significant molecule isolated from a plant called Combretum caffrum growing in South Africa, and it has been determined that it binds to the colchicine site of tubulin, inhibiting microtubule polymerization, thus showing a significant cytotoxic effect in a wide variety of preclinical tumor models [13][14][15][16][17][18] . CA-4 has a short biological half-life, low bioavailability and easily undergoes cis −trans isomerization in heat, light, and protic media, forming the inactive trans form from the active cis form [19] . The simple structure of CA-4 has allowed researchers to investigate a wide variety of CA-4 analogs in anticancer drug development programs worldwide. ...
... Previously, we examined the effects of substituents in the amide moiety of indoleacrylamide derivatives [16][17][18][19][20][21] . Continuing these studies, we aimed to determine whether substitution in the prop-2-en-1-one linker had an effect on the bioactivity of these compounds with tubulin. ...
Novel compounds containing polar and nonpolar substitutions on the prop-2-en-1-on linker of the trans-indol-3-ylacrylamide scaffold were designed by modeling within the colchicine site of tubulin and then synthesized to determine the role of such substitutions on tubulin polymerization. We first determined the in vitro antiproliferation activities of the compounds against cancer cell lines with a particular focus on hepatocellular carcinoma. The results indicated that five of the compounds showed moderate antitumor activities. When the tubulin polymerization inhibitory effect of these compounds was evaluated, compound 13 was determined to be a tubulin polymerization inhibitor. Furthermore, cell cycle analysis for compound 13 resulted in G2/M-phase arrest in Huh7 cells. The results indicated that polar substitutions on the indole acrylamide scaffold enhance potency against tubulin polymerization. However, the substitution-related bioactivity shifting was not observed on the cancer cell lines since the inhibition mechanisms of the compounds may vary.
... Fig. 1) is a significant molecule isolated from a plant called Combretum caffrum growing in South Africa, and it has been determined that it binds to microtubules' colchicine binding site, inhibiting microtubule polymerization, thus showing a significant cytotoxic effect in a wide variety of preclinical tumor models [11][12][13][14][15][16]. CA-4 has a short biological half-life, low bioavailability and easily undergoes cis−trans isomerization in heat, light, and protic media, forming the inactive trans form from the active cis form [17]. CA-4 phosphate (CA-4P), a phosphate prodrug of CA-4, has higher bioavailability and 10 times stronger cytotoxic effect than CA-4. The vascular damaging properties of CA-4 have prompted clinical evaluation of CA-4P derivatives. ...
... In their other study, the incorporation of the bridging NH and the imidazo-pyridine/pyrazine moieties 34 (Fig. 4) as a linker between the bridging alkene motif and the aryl group has provided the flexibility, and those compounds have exhibited significant tubulin polymerization inhibition and disruption of tubulin-microtubule dynamics similar to that of CA-4 [58]. They have recently reported that the synthesis of 4-aryl-5-aroyl-1Himidazole-2-amines as a potent anti-tumor agent against many cancer cell lines has attributed its property to inhibit tubulin assembly [17]. All 4-aryl-5-aroyl substituted 1H-imidazole-2-amine analogues have shared the common structure of trimethoxy benzene "ring A" with imidazole ring, with the difference in ring B among the substituents. ...
... Similarly, compound 35 has exhibited striking results in MCF 10A, MCF-7, L929 cells and B16F10 cells with the IC 50 values of 1.9, 0.12, 1.6, and 0.41 µM, respectively. The results indicate its interaction with tubulin by interacting with hydrophobic amino acids of the colchicine binding site [17]. ...
Cancer is one of the leading causes of fatality and mortality worldwide. Investigations on developing therapeutic strategies for cancer are supported throughout the world. The massive achievements in molecular sciences involving biochemistry, molecular chemistry, medicine, and pharmacy, and high throughput techniques such as genomics and proteomics have helped to create new potential drug targets for cancer treatment. Microtubules are very attractive targets for cancer therapy because of the crucial roles they play in cell division. In recent years, lots of efforts have been put into the identification of new microtubule-targeting agents (MTAs) in anticancer therapy. Combretastatin A-4 (CA-4) is a natural compound that binds to microtubules’ colchicine binding site and inhibits microtubule polymerization. Due to CA-4’s structural simplicity, many analogs have been synthesized. This article summarizes the new molecule development efforts to reach CA-4 analogs by modifications on its pharmacophore groups, published since 2015.
