Design, synthesis, antitumor activities and biological studies of novel diaryl substituted fused heterocycles as dual ligands targeting tubulin and katanin

Dual-targeting inhibitors involving tubulin for the treatment of cancer

Combination therapies play a pivotal role in cancer treatment due to the intricate nature of the disease. Tubulin, a protein crucial for cellular functions, is a prime target in tumor therapy as it regulates microtubule dynamics. Combining tubulin inhibitors with other different inhibitors as dual targeting inhibitors has shown synergistic anti-tumor effects, amplifying therapeutic outcomes. Despite clinical approval of several tubulin inhibitors, their efficacy is hampered by drug resistance and toxic side effects. Dual targeting inhibitors of tubulin and other cancer-related pathways have emerged as vital components in cancer therapy, with promising prospects in both market availability and ongoing clinical trials. The rational design of hybrid inhibitors targeting both pathways presents an innovative approach to combatting cancer. However, despite the potent anti-tumor activity exhibited by several compounds, research on their anti-angiogenic potential remains limited. This review emphasizes the significance of tubulin based dual-target inhibitors, elucidating their mechanisms of action. Recent advances in exploring therapeutic efficacy, toxicity profiles, and challenges such as MDR are discussed. By presenting the research progress of tubulin based dual-target inhibitors as potential anticancer agents, this study delivers valuable insights for the development of more efficient drugs for cancer therapy.

Design, synthesis and biological evaluation of novel diaryl-substituted fused nitrogen heterocycles as tubulin polymerization inhibitors to overcome multidrug resistance in vitro and in vivo

Microtubule-targeting agents (MTAs) are considered as one of the most successful chemotherapy drugs for lung adenocarcinoma (LUAD). However, the clinical application of MTAs is often significantly plagued by multidrug resistance (MDR). To overcome this limitation in the quest of more effective MTAs for tumor therapy, a series of novel diaryl-substituted nitrogenous fused heterocycles were designed, synthesized and evaluated. Through four rounds of structure-activity relationship studies, the benzoimidazole derivative 37 was identified as a potent cytotoxic agent against both paclitaxel-sensitive and -resistant A549 (A549/T) cells, effectively overcoming multidrug resistance of A549/T cells against various MTAs. Mechanistic investigations revealed that 37 could disrupt microtubule assembly and induce cell cycle arrest at the G2/M phase, and hence trigger the cell apoptosis. Furthermore, 37 was found to be a poor substrate for P-glycoprotein (P-gp), a major contributor to multidrug resistance, and could reduce the level of P-gp in resistant cells, thereby effectively overcoming P-gp-mediated multidrug resistance. Notably, 37 exhibited higher liver microsomal stability and better water solubility than those of the reference combretastatin A-4 (CA-4). In vivo studies using an A549/T xenograft model demonstrated that 37 significantly inhibited tumor growth without obvious toxicity, outperforming the positive controls CA-4 and paclitaxel. As a novel tubulin polymerization inhibitor, compound 37 is marked by potent anticancer activity and remarkable anti-MDR properties. These salient features, coupled with the low toxicity of 37, would render it quite promising as a lead for further drug development towards clinical treatment of multidrug-resistant LUAD.

Exploring purine analogues as inhibitors against Katanin, a microtubule severing enzyme using molecular modeling approach

Katanin, a key protein in cellular architecture, plays a crucial role in severing microtubules, which are vital components of the cytoskeleton. Given its central involvement in cell division and proliferation, katanin represents a promising target for therapeutic intervention, particularly in cancer treatment. Inhibiting katanin's function could potentially hinder the uncontrolled growth of cancerous cells, making it an attractive target for novel anti-cancer therapies. Previous studies have shown that purine-based compounds exhibit a strong affinity for microtubule-severing enzymes. In this study, we aim to identify potential purine-type inhibitors of katanin using molecular modeling techniques. A total of 276,280 purine-type compounds from the PubChem database were subjected to structure-based high-throughput virtual screening, followed by ADME prediction, PASS analysis, and molecular docking studies. These efforts led to the identification of two potent compounds: PubChem CID 122589735 and 123629569, which demonstrated strong binding interactions with katanin. Molecular dynamics simulations further revealed that these compounds effectively altered katanin's conformation when compared to ATP. Additionally, binding energy calculations indicated that PubChem CID 122589735 exhibited the strongest binding affinity for katanin, with the binding free energy ranking as follows: 122589735 > 123629569 > ATP. Our findings suggest that the screened compounds, particularly PubChem CID 122589735, hold promise as potential katanin inhibitor. These compounds could play a significant role in the development of new anti-cancer therapies targeting a variety of carcinoma. Future research, including in vitro and in vivo studies, is essential to assess the efficacy and safety of these inhibitors, paving the way for innovative cancer treatments.

Dual-target inhibitors of colchicine binding site for cancer treatment

Colchicine binding site inhibitors (CBSIs) have attracted much attention due to their antitumor efficacies and the advantages of inhibiting angiogenesis and overcoming multidrug resistance. However, no CBSI has been currently approved for cancer treatment due to the insufficient efficacies, serious toxicities and poor pharmacokinetic properties. Design of dual-target inhibitors is becoming a potential strategy for cancer treatment to improve anticancer efficacy, decrease adverse events and overcome drug resistance. Therefore, we reviewed dual-target inhibitors of colchicine binding site (CBS), summarized the design strategies and the biological activities of these dual-target inhibitors, expecting to provide inspiration for developing novel dual inhibitors based on CBS.

Discovery of Novel Diaryl-Substituted Fused Heterocycles Targeting Katanin and Tubulin with Potent Antitumor and Antimultidrug Resistance Efficacy

Disrupting microtubule dynamics has emerged as a promising strategy for cancer treatment. However, drug resistance remains a challenge hindering the development of microtubule-targeting agents. In this work, a novel class of diaryl substituted fused heterocycles were designed, synthesized, and evaluated, which were demonstrated as effective dual katanin and tubulin regulators with antitumor activity. Following three rounds of stepwise optimization, compound 21b, featuring a 3H-imidazo[4,5-b]pyridine core, displayed excellent targeting capabilities on katanin and tubulin, along with notable antiproliferative and antimetastatic effects. Mechanistic studies revealed that 21b disrupts the microtubule network in tumor cells, leading to G2/M cell cycle arrest and apoptosis induction. Importantly, 21b exhibited significant inhibition of tumor growth in MDA-MB-231 and A549/T xenograft tumor models without evident toxicity and side effects. In conclusion, compound 21b presents a novel mechanism for disrupting microtubule dynamics, warranting further investigation as a dual-targeted antitumor agent with potential antimultidrug resistance properties.

Structure-based approaches for the design of 6-aryl-1-(3,4,5-trimethoxyphenyl)-1H-benzo[d][1,2,3]triazoles as tubulin polymerization inhibitors

The colchicine binding site on tubulin has been widely acknowledged as an attractive target for anticancer drug exploitation. Here, we reported the structural optimization of the lead compound 4, which was proved in our previous work as a colchicine binding site inhibitor (CBSI). Based on docking researches for the active binding conformation of compound 4, a series of novel 6-aryl-1-(3,4,5-trimethoxyphenyl)-1H-benzo[d][1,2,3]triazole derivatives (9a-9x) were developed by replacing a CH group in the 1H-benzo[d]imidazole skeleton of compound 4 with a nitrogen atom as a hydrogen bond acceptor. Among them, compound 9a showed the strongest antiproliferative activity with IC50 values ranging from 14 to 45 nM against three human cancer cell lines (MCF-7, SGC-7901 and A549), lower than that of compound 4. Mechanistic studies indicated that compound 9a could inhibit tubulin polymerization, destroy the microtubule skeleton, block the cell cycle in G2/M phase, induce cancer cell apoptosis, prevent cancer cell migration and colony formation. Moreover, compound 9a significantly inhibited tumor growth in vivo without observable toxicity in the mice 4T1 xenograft tumor model. In conclusion, this report shows a successful case of the structure-based design approach of a potent tubulin polymerization inhibitor for cancer treatment.

Design, synthesis and mechanistic study of new dual targeting HDAC/tubulin inhibitors

Aim: The purpose of this work is to create and synthesize a new class of chemicals: 3-cyano-2-substituted pyridine compounds with expected multitarget inhibition of histone deacetylase (HDAC) and tubulin. Materials & methods: The target compounds (3a-c, 4a-c and 5a-c) were synthesized utilizing 6-(4-methoxyphenyl)-2-oxo-4-(3,4,5-trimethoxyphenyl)-3-cyanopyridine, with various linkers and zinc-binding groups (ZBGs). Results: Most of the tested compounds showed promising growth inhibition, and hydroxamic acid-containing hybrids possessed higher HDAC inhibition than other ZBGs. Compound 4b possessed the highest potency; however, it showed the most tubulin polymerization inhibition. Docking studies displayed good binding into HDAC1 and six pockets and tubulin polymerization protein. Conclusion: Compound 4b could be considered a good antitumor candidate to go further into in vivo and clinical studies.

Discovery of chiral 1,4-diarylazetidin-2-one-based hydroxamic acid derivatives as novel tubulin polymerization inhibitors with histone deacetylase inhibitory activity

Tubulin and histone deacetylase have been clinically proven as promising targets for cancer therapy. Herein, we describe the design and synthesis of chiral 1,4-diarylazetidin-2-one-based hydroxamic acids as novel tubulin/HDAC dual inhibitors. Among them, compound 12a was validated to effectively disrupt tubulin polymerization, and exhibited potent HDAC1/8 inhibitory activities. Meanwhile, 12a showed good antiproliferative activities against four tumor cell lines. Further studies showed 12a works through blocking cellular cycle, inducing apoptosis and inhibiting colony formation. In addition, 12a has suitable physicochemical properties and high liver microsomal metabolic stability. Importantly, compound 12a was found to exhibit significant antitumor efficacy in vivo, thus warranting it as a promising tubulin/HDAC dual inhibitor for further development.

Imidazopyridine, a promising scaffold with potential medicinal applications and structural activity relationship (SAR): recent advances

Imidazopyridine scaffold has gained tremendous importance over the past few decades. Imidazopyridines have been expeditiously used for the rationale design and development of novel synthetic analogs for various therapeutic disorders. A wide variety of imidazopyridine derivatives have been developed as potential anti-cancer, anti-diabetic, anti-tubercular, anti-microbial, anti-viral, anti-inflammatory, central nervous system (CNS) agents besides other chemotherapeutic agents. Imidazopyridine heterocyclic system acts as a key pharmacophore motif for the identification and optimization of lead structures to increase medicinal chemistry toolbox. The present review highlights the medicinal significances of imidazopyridines for their rationale development as lead molecules with improved therapeutic efficacies. This review further emphasis on the structure-activity relationships (SARs) of the various designed imidazopyridines to establish a relationship between the key structural features versus the biological activities.Communicated by Ramaswamy H. Sarma.

Discovery of a novel piperlongumine analogue as a microtubule polymerization inhibitor with potent anti-angiogenic and anti-metastatic efficacy

In an effort to discover anticancer agents with simultaneous effects on tubulin and angiogenesis, we designed and synthesized two series of piperlongumie (PL) derivatives by replacing of phenyl group with a variety of benzoheterocycle (series II) or cyclizing the C7-C8 olefin into an aromatic heterocycle (series I). Most of the new compounds showed better antiproliferative activities against six cancer cell lines than the parent drug PL. Compound II-14b had the best cytotoxic profile of these two series in cancer cells, whilst being relatively low cytotoxicity against normal human cells and high potency against drug-resistant cells. It disrupted cellular microtubule networks and inhibited tubulin assembly with an IC50 value of 5.8 μM. Further studies elucidated that II-14b showed antitumor activities through multiple mechanisms, including the pruduction of abundant ROS, the dissipation of mitochondrial membrane potential, the accumulation of DNA double-strand breaks, and the induction of cell cycle in G2/M phase. More importantly, we have observed that it possesses potential anti-angiogenesis capabilities, including suppression of HUVECs cell migration, invasion, and endothelial tube formation in vitro and in vivo. In vivo assessment indicated that II-14b inhibits the growth and metastasis of MGC-803 xenograft tumour in zebrafish. These findings show that II-14b is a high-efficacy and non-toxic antitumor agent.

Discovery of Simple Diacylhydrazine-Functionalized Cinnamic Acid Derivatives as Potential Microtubule Stabilizers

To develop novel microtubule-binding agents for cancer therapy, an array of N-cinnamoyl-N'-(substituted)acryloyl hydrazide derivatives were facilely synthesized through a two-step process. Initially, the antiproliferative activity of these title compounds was explored against A549, 98 PC-3 and HepG2 cancer cell lines. Notably, compound I₂₃ exhibited the best antiproliferative activity against three cancer lines with IC₅₀ values ranging from 3.36 to 5.99 μM and concurrently afforded a lower cytotoxicity towards the NRK-52E cells. Anticancer mechanism investigations suggested that the highly bioactive compound I₂₃ could potentially promote the protofilament assembly of tubulin, thus eventually leading to the stagnation of the G2/M phase cell cycle of HepG2 cells. Moreover, compound I₂₃ also disrupted cancer cell migration and significantly induced HepG2 cells apoptosis in a dosage-dependent manner. Additionally, the in silico analysis indicated that compound I₂₃ exhibited an acceptable pharmacokinetic profile. Overall, these easily prepared N-cinnamoyl-N'-(substituted)acryloyl hydrazide derivatives could serve as potential microtubule-interacting agents, probably as novel microtubule-stabilizers.

Emerging role of microtubule-associated proteins on cancer metastasis

The major cause of death in cancer patients is strongly associated with metastasis. While much remains to be understood, microtubule-associated proteins (MAPs) have shed light on metastatic progression’s molecular mechanisms. In this review article, we focus on the role of MAPs in cancer aggressiveness, particularly cancer metastasis activity. Increasing evidence has shown that a growing number of MAP member proteins might be fundamental regulators involved in altering microtubule dynamics, contributing to cancer migration, invasion, and epithelial-to-mesenchymal transition. MAP types have been established according to their microtubule-binding site and function in microtubule-dependent activities. We highlight that altered MAP expression was commonly found in many cancer types and related to cancer progression based on available evidence. Furthermore, we discuss and integrate the relevance of MAPs and related molecular signaling pathways in cancer metastasis. Our review provides a comprehensive understanding of MAP function on microtubules. It elucidates how MAPs regulate cancer progression, preferentially in metastasis, providing substantial scientific information on MAPs as potential therapeutic targets and prognostic markers for cancer management.

Targeting the tumor microenvironment by an enzyme-responsive prodrug of tubulin destabilizer for triple-negative breast cancer therapy with high safety

In response to the long-term potential toxicity concerns of tubulin destabilizer, an enzyme-responsive prodrug therapy for triple-negative breast cancer was developed based on the different β-glucuronidase levels between tumor and normal tissues in this study. All the prodrugs synthesized herein showed remarkable stability in phosphate buffer and bovine serum solution, among which 17a was found to be more susceptible to enzymatic cleavage. 17a exhibited excellent selectivity between the in vitro antiproliferative activities against β-glucuronidase-pretreated and -untreated cancer cells (IC₅₀ (+Enz) = 8.9-15.7 nM, IC₅₀ (-Enz) > 50 μM), along with favorable liver microsomal metabolic stability and improved aqueous solubility. Furthermore, as a candidate prodrug 17a showed potent antitumor efficacy in MDA-MB-231 xenograft mouse model without causing perceptible injury to organs. Importantly, 17a exhibited superior safety profiles with higher LD₅₀ value and no perceivable cardiotoxicity, which was a major dose-limiting adverse effect for the parent compound 1. These salient toxicity-reduced effects of 17a would merit further in-depth assessment of this compound for preclinical therapeutic usages.

Design, synthesis and bioevaluation of 6-aryl-1-(3,4,5-trimethoxyphenyl)-1H-benzo[d]imidazoles as tubulin polymerization inhibitors

A series of new 6-aryl-1-(3,4,5-trimethoxyphenyl)-1H-benzo[d]imidazoles as tubulin polymerization inhibitors targeting the colchicine-binding site were designed to restrict bioactive configuration of (Z,E)-vinylogous CA-4. All of the target compounds were synthesized and then evaluated for their in vitro antiproliferative activities. Among them, 2a exhibited the most potent activities against three cancer cell lines with IC₅₀ values in the range of 0.037-0.20 μM. Further mechanism studies revealed that 2a inhibited tubulin polymerization, disrupted cell microtubule networks, arrested the cell cycle at G2/M phase, induced apoptosis and hindered cancer cell migration. Moreover, 2a displayed significant in vivo antitumor efficacy in 4T1-xenograft mice model with tumor growth inhibition rate of 52% at the dose of 2.5 mg/kg. Colchicine competition assay and the docking model of 2a in complex with tubulin showed that 2a acted at the colchicine-binding site.

Angiogenesis, Anti-Tumor, and Anti-Metastatic Activity of Novel α-Substituted Hetero-Aromatic Chalcone Hybrids as Inhibitors of Microtubule Polymerization

A library of new heteroaromatic ring-linked chalcone analogs were designed and synthesized of these, compound 7m with α-CH₃ substitution and bearing a benzofuran ring, displaying the most potent activity, with IC₅₀ values of 0.07–0.183 µM against three cancer cells. Its low cytotoxicity toward normal human cells and strong potency on drug-resistant cells revealed the possibility for cancer therapy. It also could moderately inhibit in vitro tubulin polymerization with an IC₅₀ value of 12.23 µM, and the disruption of cellular architecture in MCF-7 cells was observed by an immunofluorescence assay. Cellular-based mechanism studies elucidated that 7m arrested the cell cycle at the G2/M phase and induced apoptosis by regulating the expression levels of caspases and PARP protein. Importantly, the compound 7 m was found to inhibit HUVEC tube formation, migration, and invasion in vitro. In vivo assay showed that 7m could effectively destroy angiogenesis of zebrafish embryos. Furthermore, our data suggested that treatment with 7m significantly reduced MCF-7 cell metastasis and proliferation in vitro and in zebrafish xenograft. Collectively, this work showed that chalcone hybrid 7m deserves further investigation as dual potential tubulin polymerization and angiogenesis inhibitor.

Discovery of facile amides-functionalized rhodanine-3-acetic acid derivatives as potential anticancer agents by disrupting microtubule dynamics

Microtubule dynamics are crucial for multiple cell functions, and cancer cells are particularly sensitive to microtubule-modulating agents. Here, we describe the design and synthesis of a series of (Z)-2-(5-benzylidene-4-oxo-2-thioxothiazolidin-3-yl)-N-phenylacetamide derivatives and evaluation of their microtubule-modulating and anticancer activities in vitro. Proliferation assays identified I₂₀ as the most potent of the antiproliferative compounds, with 50% inhibitory concentrations ranging from 7.0 to 20.3 µM with A549, PC-3, and HepG2 human cancer cell lines. Compound I₂₀ also disrupted cancer A549 cell migration in a concentration-dependent manner. Immunofluorescence microscopy, transmission electron microscopy, and tubulin polymerisation assays suggested that compound I₂₀ promoted protofilament assembly. In support of this possibility, computational docking studies revealed a strong interaction between compound I₂₀ and tubulin Arg β369, which is also the binding site for the anticancer drug Taxol. Our results suggest that (Z)-2-(5-benzylidene-4-oxo-2-thioxothiazolidin-3-yl)-N-phenylacetamide derivatives could have utility for the development of microtubule-stabilising therapeutic agents.

The characteristics of Raman spectroscopy of fenbendazole-gold nanoparticles based on the chemical adsorption effect

Fenbendazole, a benzimidazole derivative with anti-tubulin polymerization properties, has been widely used in the treatment of parasitic infections. Because of its anticancer activity similar to that of many anticancer drugs, low cost and few side effects, fenbendazole has attracted wide research attention. The chemical adsorption of fenbendazole and gold nanoparticles are studied by the UV-Vis spectrophotometry, density functional method, Raman spectroscopy and surface-enhanced Raman spectroscopy. By comparing and analyzing the theoretical and experimental Raman spectra, this paper explains the reasons for the difference between the theoretical and experimental Raman spectra. Meanwhile, it is also found that the frequencies at 851 cm^-1, 1222 cm^-1, 1425 cm^-1 and 1566 cm^-1 are greatly enhanced. It is found that imidazole is adsorbed vertically to the surface of the substrate. It is concluded that Fenbendazole is vertically adsorbed on the surface of AuNPs through imidazole.

Recent Progress on Tubulin Inhibitors with Dual Targeting Capabilities for Cancer Therapy

Microtubules play a crucial role in multiple cellular functions including mitosis, cell signaling, and organelle trafficking, which makes the microtubule an important target for cancer therapy. Despite the great successes of microtubule-targeting agents in the clinic, the development of drug resistance and dose-limiting toxicity restrict their clinical efficacy. In recent years, multitarget therapy has been considered an effective strategy to achieve higher therapeutic efficacy, in particular dual-target drugs. In terms of the synergetic effect of tubulin and other antitumor agents such as receptor tyrosine kinases inhibitors, histone deacetylases inhibitors, DNA-damaging agents, and topoisomerase inhibitors in combination therapy, designing dual-target tubulin inhibitors is regarded as a promising approach to overcome these limitations and improve therapeutic efficacy. In this Perspective, we discussed rational target combinations, design strategies, structure-activity relationships, and future directions of dual-target tubulin inhibitors.

Efficient Route for the Synthesis of Diverse Heteroannelated 5-Cyanopyridines

The new efficient, convenient protocol for the synthesis of heteroannelated 3-cyanopyridines and pyrimidines starting from diverse aminoheterocycles and 3,3-dimethoxy-2-formylpropionitrile sodium salt was elaborated. The advantages and improvements of the procedure compared to previously known methods are shown. The scope and limitations of the method are determined. The impact of the structural features on regioselectivity are discussed. The preparativeness, scalability, and application scope of the elaborated protocol are demonstrated by the synthesis of five heteroannelated 3-cyanopyridines in quantities up to 100 grams.

Synthesis and biological evaluation of new 2-methoxyestradiol derivatives: Potent inhibitors of angiogenesis and tubulin polymerization

Here, we report the structural optimization of a hit natural compound, 2-ME₂ (2-methoxyestradiol), which exhibited inhibitory activity but low potency on tubulin polymerization, anti- angiogenesis, MCF-7 proliferation and metastasis in vitro and in vivo. A novel series of 3,17-modified and 17-modified analogs of 2-ME₂ were synthesized and investigated for their antiproliferative activity against MCF-7 and another five different human cancer cell lines leading to the discovery of 9i. 9i bind to tubulin colchicine site tightly, inhibited tubulin polymerization and disrupted cellular microtubule networks. Cellular mechanism studies revealed that 9i could induce G2/M phase arrest by down-regulated expression of p-Cdc2, P21 and cell apoptosis by regulating apoptosis-related proteins (Parp, Caspase families) in a dose-dependent manner. Importantly, 9i significantly inhibited HUVEC tube formation, proliferation, migration and invasion. The inhibitory effect against angiogenesis in vivo was confirmed by zebrafish xenograft. Furthermore, 9i could effectively inhibit the proliferation and metastasis of MCF-7 cells in vitro and in zebrafish xenograft. The satisfactory physicochemical property and metabolic stability of 9i further indicated that it can act as a promising and potent anti-angiogenesis, inhibiting proliferation and metastasis of breast cancer agent via targeting tubulin colchicine binding site.

Design, Synthesis, and Activity Evaluation of Novel Acyclic Nucleosides as Potential Anticancer Agents In Vitro and In Vivo

In the present work, 103 novel acyclic nucleosides were designed, synthesized, and evaluated for their anticancer activities in vitro and in vivo. The structure-activity relationship (SAR) studies revealed that most target compounds inhibited the growth of colon cancer cells in vitro, of which 3-(6-chloro-9H-purin-9-yl)dodecan-1-ol (9b) exhibited the most potent effect against the HCT-116 and SW480 cells with IC50 values of 0.89 and 1.15 μM, respectively. Furthermore, all of the (R)-configured acyclic nucleoside derivatives displayed more potent anticancer activity compared to their (S)-counterparts. Mechanistic studies revealed that compound 9b triggered apoptosis in the cancer cell lines via depolarization of the mitochondrial membrane and effectively inhibited colony formation. Importantly, compound 9b inhibited the growth of the SW480 xenograft in a mouse model with low systemic toxicity. These results indicated that acyclic nucleoside compounds are viable as potent and effective anticancer agents, and compound 9b may serve as a promising lead compound that merits further attention in future anticancer drug discovery.

Novel diaryl-2H-azirines: Antitumor hybrids for dual-targeting tubulin and DNA

Multiple-target drugs may achieve better therapeutic effect via different pathways than single-target ones, especially for complex diseases. Tubulin and DNA are well-characterized molecular targets for anti-cancer drug development. A novel class of diaryl substituted 2H-azirines were designed based on combination of pharmacophores from Combretastatin A-4 (CA-4) and aziridine-type alkylating agents, which are known tubulin polymerization inhibitor and DNA damaging agents, respectively. The antitumor activities of these compounds were evaluated in vitro and 6h showed the most potent activities against four cancer cell lines with IC₅₀ values ranging from 0.16 to 1.40 μM. Further mechanistic studies revealed that 6h worked as a bifunctional agent targeting both tubulin and DNA. In the nude mice xenograft model, 6h significantly inhibited the tumor growth with low toxicity, demonstrating the promising potential for further developing novel cancer therapy with a unique mechanism.

4'-O-Methylbroussochalcone B as a novel tubulin polymerization inhibitor suppressed the proliferation and migration of acute myeloid leukaemia cells

BACKGROUND

Recent years, survival rates of human with high-risk acute myeloid leukaemia (AML) have not raised substantially. This research aimed to investigate the role of 4'-O-Methylbroussochalcone B, for the treatment of human AML.

METHODS

Firstly, we evaluated the effects of six chalcones on AML cells activity by MTT assay. Immunofluorescence staining, tubulin polymerization assay and N,N'-ethylenebis (iodoacetamide) (EBI) competition assay were performed on ML-2 cells. Transwell and apoptosis assay were also utilized in ML-2 cells and OCI-AML5 cells. The expressions of migration-related proteins, apoptosis-related proteins and Wnt/β-catenin pathway were detected by Western Blot.

RESULTS

The results found six chalcones exhibited the anti-proliferative activity against different AML cell lines. Based on the results of immunofluorescence staining, tubulin polymerization assay and EBI competition assay, 4'-O-Methylbroussochalcone B was discovered to be a novel colchicine site tubulin polymerization inhibitor. 4'-O-Methylbroussochalcone B could induce apoptosis, inhibit proliferation and migration of ML-2 cells and OCI-AML5 cells. The cells were arrested in the G2-M phase by the treatment of 4'-O-Methylbroussochalcone B. In addition, 4'-O-Methylbroussochalcone B regulated MAPK and Wnt/β-catenin pathways in AML cells.

CONCLUSION

4'-O-Methylbroussochalcone B might inhibit proliferation and migration of the AML cells by MAPK and Wnt/β-catenin pathways as a tubulin polymerization inhibitor. It is promising for 4'-O-Methylbroussochalcone B to become a new drug to treat AML.

Potent Quinoline-Containing Combretastatin A-4 Analogues: Design, Synthesis, Antiproliferative, and Anti-Tubulin Activity

A novel series of quinoline derivatives of combretastatin A-4 incorporating rigid hydrazone and a cyclic oxadiazole linkers were synthesized and have demonstrated potent tubulin polymerization inhibitory properties. Many of these novel derivatives have shown significant antiproliferative activities in the submicromolar range. The most potent compound, 19h, demonstrated superior IC50 values ranging from 0.02 to 0.04 µM against four cancer cell lines while maintaining low cytotoxicity in MCF-10A non-cancer cells, thereby suggesting 19h's selectivity towards proliferating cancer cells. In addition to tubulin polymerization inhibition, 19h caused cell cycle arrest in MCF-7 cells at the G2/M phase and induced apoptosis. Collectively, these findings indicate that 19h holds potential for further investigation as a potent chemotherapeutic agent targeting tubulin.