Evodiamine-inspired dual inhibitors of histone deacetylase 1 (HDAC1) and topoisomerase 2 (TOP2) with potent antitumor activity

Semisynthesis of Glycosmis pentaphylla Alkaloid Derivatives: Pyranoacridone-Hydroxamic Acid Cytotoxic Conjugates with HDAC and Topoisomerase II α Dual Inhibitory Activity

Inspired by our previous efforts in the semisynthetic modification of naturally occurring pyranoacridones, we report the targeted design and semisynthesis of dual inhibitors of HDAC and topoisomerase II α (Topo II α) derived from Glycosmis pentaphylla des-N-methylacronycine (1) and noracronycine (8) pyranoacridone alkaloids. Designed from the clinically approved SAHA, the cytotoxic pyranoacridone nuclei from the alkaloids served as the capping group, while a hydroxamic acid moiety functioned as the zinc-binding group. Out of 16 compounds evaluated in an in vitro cytotoxicity assay, KT32 (10c) with noracronycine (8) as the capping group and five-carbon linker hydroxamic acid side chains showed good cytotoxic activity with IC50 values of 1.0, 1.5, and 0.3 μM on MCF-7, CALU-3, and SCC-25 cell lines, respectively. KT32 (10c) showed potent HDAC inhibitory activity and partial Topo II α inhibitory activity in both enzyme assays. The SAR results strongly aligned with the predicted binding affinities from the molecular docking study. KT32 (10c) was further explored for a preliminary mechanistic understanding of SCC-25 cell lines. Flow cytometry analysis suggests that KT32 (10c) induces cell death through apoptosis, as evidenced by the substantial increase in the population of late apoptotic cells.

Indolo[3,2-c]isoquinoline Hydroxamic Acid Derivatives as Novel Orally Topoisomerase-Histone Deacetylase Dual Inhibitors for NSCLC Therapy

Based on the synergistic effects of topoisomerase (Top) inhibitors and histone deacetylase (HDAC) inhibitors in cancer therapy, a series of novel Top/HDAC dual inhibitors were designed and synthesized herein. The optimal compound 31 was identified to simultaneously inhibit both Tops and HDACs with potent antiproliferative activity against nonsmall cell lung cancer (NSCLC). Mechanistic studies indicated that compound 31 with increasing reactive oxygen species levels damages DNA, inhibiting cancer cell colony formation and migration and inducing both cancer cell apoptosis and cycle arrest. Noteworthily, compound 31 was orally active in the NSCLC xenograft model, and its antitumor efficacy (TGI = 77.5%, 100 mg/kg) was superior to that of HDAC inhibitor SAHA and SAHA in combination with the Top inhibitor irinotecan. Consequently, this work highlights the therapeutic potential of compound 31 as the Top/HDAC dual inhibitor in NSCLC therapy and provides valuable lead compounds for the further development of antitumor agents in solid tumor therapy.

Design, synthesis and biological activity of oxyevodiamine-based histone deacetylase 6 inhibitors

Histone deacetylase 6 (HDAC6) was a potential target for Alzheimer's disease (AD). In this study, a series of novel oxyevodiamine-based HDAC6 inhibitors with a variety of linker moieties were designed, synthesized and evaluated. Compound 12 with a benzyl linker was identified as a high potent and selective HDAC6 inhibitor. It inhibited HDAC6 with an IC50 value of 6.2 nM and was more than 200 fold selectivity over HDAC1. It also had lower cytotoxicity and higher anti-H2O2 activity in vitro comparing with other derivatives. Compound 12 might be a good lead as novel HDAC6 inhibitor for the treatment of AD.

Evodiamine: A Extremely Potential Drug Development Candidate of Alkaloids from Evodia rutaecarpa

Evodiamine (EVO) is a tryptamine indole alkaloid and the main active ingredient in Evodia rutaecarpa. In recent years, the antitumor, cardioprotective, anti-inflammatory, and anti-Alzheimer's disease effects of EVO have been reported. EVO exerts antitumor effects by inhibiting tumor cell activity and proliferation, blocking the cell cycle, promoting apoptosis and autophagy, and inhibiting the formation of the tumor microvasculature. However, EVO has poor solubility and low bioavailability. Several derivatives with high antitumor activity have been discovered through the structural optimization of EVO, and new drug delivery systems have been developed to improve the solubility and bioavailability of EVO. Current research found that EVO could have toxic effects, such as hepatotoxicity, nephrotoxicity, and cardiac toxicity. This article reviews the pharmacological activity, derivatives, drug delivery systems, toxicity, and pharmacokinetics of EVO and provides research ideas and references for its further in-depth development and clinical applications.

PROTAC derivatization of natural products for target identification and drug discovery: Design of evodiamine-based PROTACs as novel REXO4 degraders

INTRODUCTION

Natural products (NPs) play a crucial role in the development of therapeutic drugs. However, it is still highly challenging to identify the targets of NPs. Besides, NPs usually exert their pharmacological activities via acting on multiple targets or pathways, which also poses great difficulties for the target identification of NPs.

OBJECTIVES

Inspired by our continuous efforts in designing drug-like protein degraders, this study introduced a successful example for the target identification and drug discovery of natural products evodiamine by employing PROTAC technology.

METHODS

Taking advantages of proteolysis targeting chimera (PROTAC), herein an integrated strategy combining PROTAC derivatization, quantitative proteomic analysis and binding affinity validation was developed for target identification and drug discovery of antitumor NP evodiamine.

RESULTS

In this study, both highly potent PROTACs and negative controls were designed for quantitative proteomic analysis. Furthermore, REXO4 was confirmed as a direct target of 3-fluoro-10-hydroxylevodiamine, which induced cell death through ROS. In addition, the PROTAC 13c effectively degraded REXO4 both in vitro and in vivo, leading to potent antitumor activities and reduced toxic side effects.

CONCLUSION

In summary, we developed an integrated strategy for the target identification and drug discovery of NPs, which was successfully applied to the PROTAC derivatization and target characterization of evodiamine. This proof-of-concept study highlighted the superiority of PROTAC technology in target identification of NPs and accelerated the process of NPs-based drug discovery, exhibiting broad application in NP-based drug development.

Discovery of Novel HDAC3 Inhibitors with PD-L1 Downregulating/Degrading and Antitumor Immune Effects

Targeting the programmed cell death-1/ligand 1 (PD-1/PD-L1) pathway is one of the most promising cancer treatment strategies. Studies have shown that HDAC inhibitors can enhance the antitumor immune response by modulating the expression of PD-L1. Herein, we designed and synthesized a series of novel hydrazide-based small molecule HDAC inhibitors; among them, compound HQ-30 showed selective HDAC3 inhibition (IC50 = 89 nM) and remarkable PD-L1-degrading activity (DC50 = 5.7 μM, Dmax = 80% at 10 μM). Further studies revealed that HQ-30 induced the degradation of PD-L1 by regulating cathepsin B (CTSB) in the lysosomes. Further, HQ-30 could enhance the infiltration of CD3+ CD4+ helper T and CD3+ CD8+ cytotoxic T cells in tumors, thus activating the tumor immune microenvironment. Moreover, HQ-30 possessed a benign toxicity profile (LD50 > 1000 mg/kg) and favorable pharmacokinetic properties (F = 57%). Taken together, HQ-30 is worthy of further investigation as a small molecule-based epigenetic modulator of tumor immunotherapy.

Rutaecarpine-inspired scaffold-hopping strategy and Ullmann cross-coupling based synthetic approach: Identification of pyridopyrimidinone-indole based novel anticancer chemotypes

Natural products as starting templates have shown historically major contribution to development of drugs. Inspired by the structure-function of an anticancer natural alkaloid Rutaecarpine, the Scaffold-hopped Acyclic Analogues of Rutaecarpine (SAAR) with 'N'-atom switch (1°-hop) and ring-opening (2°-hop) were investigated. A new synthetic route was developed for an effective access to the analogues, i.e. 2-indolyl-pyrido[1,2-a]pyrimidinones, which involved preparation of N-Boc-N'-phthaloyltryptamine/mexamine-bromides and pyridopyrmidinon-2-yl triflate, a nickel/palladium-catalysed Ullmann cross-coupling of these bromides and triflate, deprotection of phthalimide followed by N-aroylation, and Boc-deprotection. Fourteen novel SAAR-compounds were prepared, and they showed characteristic antiproliferative activity against various cancer cells. Three most active compounds (11a, 11b, and 11c) exhibited good antiproliferative activity, IC50 7.7-15.8 µM against human breast adenocarcinoma cells (MCF-7), lung cancer cells (A549), and colon cancer cells (HCT-116). The antiproliferative property was also observed in the colony formation assay. The SAAR compound 11b was found to have superior potency than original natural product Rutaecarpine and an anticancer drug 5-FU in antiproliferative activities with relatively lower cytotoxicity towards normal breast epithelial cells (MCF10A) and significantly higher inhibitory effect on cancer cells' migration. The compound 11b was found to possess favourable in silico physicochemical characteristics (lipophilicity-MLOGP, TPSA, and water solubility-ESOL, and others), bioavailability score, and pharmacokinetic properties (GI absorption, BBB non-permeant, P-gp, and CYP2D6). Interestingly, the compound 11b did not show any medicinal chemistry structural alert of PAINS and Brenk filter. The study represents for the first time the successful discovery of new potent anticancer chemotypes using Rutaecarpine natural alkaloid as starting template and reaffirms the significance of natural product-inspired scaffold-hopping technique in drug discovery research.

Evaluation of 1,10-phenanthroline-based hydroxamate derivative as dual histone deacetylases/ribonucleotide reductase inhibitor with antitumor activities

BACKGROUND

Aberrant expression of histone deacetylases (HDACs) and ribonucleotide reductase (RR) enzymes are commonly observed in various cancers. Researchers are focusing on these enzymes in cancer studies with the aim of developing effective chemotherapeutic drugs for cancer treatment. Targeting both HDAC and RR simultaneously with a dual HDAC/RR inhibitor has exhibited enhanced effectiveness compared to monotherapy in cancer treatment, making it a promising strategy.

OBJECTIVES

The objective of the study is to synthesize and assess the anti-cancer properties of a 1,10-phenanthroline-based hydroxamate derivative, characterizing it as a novel dual HDAC/RR inhibitor.

METHODS

The N1-hydroxy-N8-(1,10-phenanthrolin-5-yl)octanediamide (PA), a 1,10-phenanthroline-based hydroxamate derivative, was synthesized and structurally characterized. The compound was subjected to in vitro assessments of its anti-cancer, HDAC, and RR inhibitory activities. In silico docking and molecular dynamics simulations were further studied to explore its interactions with HDACs and RRM2.

RESULTS

The structurally confirmed PA exhibited antiproliferative activity in SiHa cells with an IC50 of 16.43 μM. It displayed potent inhibitory activity against HDAC and RR with IC50 values of 10.80 μM and 9.34 μM, respectively. Co-inhibition of HDAC and RR resulted in apoptosis-induced cell death in SiHa cells, mediated by the accumulation of reactive oxygen species (ROS). In silico docking studies demonstrated that PA can effectively bind to the active sites of HDAC isoforms and RRM2. Furthermore, PA demonstrated a more favorable interaction with HDAC7, displaying a docking score of -9.633 kcal/mol, as compared to the standard HDAC inhibitor suberoylanilide hydroxamic acid (SAHA), which exhibited a docking score of -8.244 kcal/mol against HDAC7.

CONCLUSION

The present study emphasizes the prospect of designing a potential 1,10-phenanthroline hydroxamic acid derivative as a novel dual HDAC and RR-inhibiting anti-cancer molecule.

Design of Evodiamine-Glucose Conjugates with Improved In Vivo Antitumor Activity

Natural product evodiamine is a multitargeting antitumor lead compound. However, clinical development of evodiamine derivatives was hampered by poor water solubility and limited in vivo antitumor potency. Herein, a series of evodiamine-glucose conjugates were designed by additional targeting glucose transporter-1 (GLUT1). Compared with the lead compound, conjugate 8 exhibited obvious enhancement in water solubility and in vivo antitumor efficacy. Furthermore, the effect of GLUT1 targeting also led to lower cytotoxicity to normal cells. Antitumor mechanism studies manifested that conjugate 8 acted by Top1/Top2 dual inhibition, apoptosis induction, and G2/M cell cycle arrest, which selectively targeted tumor cells with a high expression level of GLUT1. Thus, evodiamine-glucose conjugates showed promising features as potential antitumor agents.

Targeting TOP2B as a vulnerability in aging and aging-related diseases

The ongoing trend of rapid aging of the global population has unavoidably resulted in an increase in aging-related diseases. There is an immense amount of interest in the scientific community for the identification of molecular targets that may effectively mitigate the process of aging and aging-related diseases. The enzyme Topoisomerase IIβ (TOP2B) plays a crucial role in resolving the topological challenges that occur during DNA-related processes. It is believed that the disruption of TOP2B function contributes to the aging of cells and tissues, as well as the development of age-related diseases. Consequently, targeting TOP2B appears to be a promising approach for interventions aimed at mitigating the effects of aging. This review focuses on recent advancements in the understanding of the role of TOP2B in the processing of aging and aging-related disorders, thus providing a novel avenue for the development of anti-aging strategies.

Proteolysis Targeting Chimeras (PROTACs) based on celastrol induce multiple protein degradation for triple-negative breast cancer treatment

The pursuit of single drugs targeting multiple targets has become a prominent trend in modern cancer therapeutics. Natural products, known for their multi-targeting capabilities, accessibility, and cost-effectiveness, hold great potential for the development of multi-target drugs. However, their therapeutic efficacy is often hindered by complex structural modifications and limited anti-tumor activity. In this study, we present a novel approach using celastrol (CST)-based Proteolysis Targeting Chimeras (PROTACs) for breast cancer therapy. Through rational design, we have successfully developed compound 6a, a potent multiple protein degrader capable of selectively degrading GRP94 and CDK1/4 in tumor cells via the endogenous ubiquitin-proteasome system. Furthermore, compound 6a has demonstrated remarkable inhibitory effects on cell proliferation and migration, and induction of apoptosis in 4T1 cells through cell cycle arrest and activation of the Bcl-2/Bax/cleaved Caspase-3 apoptotic pathway. In vivo administration of compound 6a has effectively suppressed tumor growth with an acceptable safety profile. Our findings suggest that the CST-based PROTACs described herein can be readily extended to other natural products, offering a potential avenue for the development of natural product-based PROTACs for cancer treatment.

Overview of the New Bioactive Heterocycles as Targeting Topoisomerase Inhibitors Useful Against Colon Cancer

Colorectal cancer (CRC) is the third most common cancer globally, with high mortality. Metastatic CRC is incurable in most cases, and multiple drug therapy can increase patients' life expectancy by 2 to 3 years. Efforts are being made to understand the relationship between topoisomerase enzymes and colorectal cancer. Some studies have shown that higher expression of these enzymes is correlated to a poor prognosis for this type of cancer. One of the primary drugs used in the treatment of CRC is Irinotecan, which can be used in monotherapy or, more commonly, in therapeutic schemes such as FOLFIRI (Fluorouracil, Leucovorin, and Irinotecan) and CAPIRI (Capecitabine and Irinotecan). Like Camptothecin, Irinotecan and other compounds have a mechanism of action based on the formation of a ternary complex with topoisomerase I and DNA providing damage to it, therefore leading to cell death. Thus, this review focused on the principal works published in the last ten years that demonstrate a correlation between the inhibition of different isoforms of topoisomerase and in vitro cytotoxic activity against CRC by natural products, semisynthetic and synthetic compounds of pyridine, quinoline, acridine, imidazoles, indoles, and metal complexes. The results revealed that natural compounds, semisynthetic and synthetic derivatives showed potential in vitro cytotoxicity against several colon cancer cell lines, and this activity was often accompanied by the ability to inhibit both isoforms of topoisomerase (I and II), highlighting that these enzymes can be promising targets for the development of new chemotherapy against CRC. Pyridine analogs were considered the most promising for this study, while the evaluation of the real potential of natural products was limited by the lack of information in their work. Moreover, the complexes, although promising, presented as the main limitation the lack of selectivity.

A review of progress in o-aminobenzamide-based HDAC inhibitors with dual targeting capabilities for cancer therapy

Histone deacetylases, as a new class of anticancer targets, could maintain homeostasis by catalyzing histone deacetylation and play important roles in regulating the expression of target genes. Due to the fact that simultaneous intervention with dual tumor related targets could improve treatment effects, researches on innovative design of dual-target drugs are underway. HDAC is known as a "sensitizer" for the synergistic effects with other anticancer-target drugs because of its flexible structure design. The synergistic effects of HDAC inhibitor and other target inhibitors usually show enhanced inhibitory effects on tumor cells, and also provide new strategies to overcome multidrug resistance. Many research groups have reported that simultaneously inhibiting HDAC and other targets, such as tubulin, EGFR, could enhance the therapeutic effects. The o-aminobenzamide group is often used as a ZBG group in the design of HDAC inhibitors with potent antitumor effects. Given the prolonged inhibitory effects and reduced toxic side effects of HDAC inhibitors using o-aminobenzamide as the ZBG group, the o-aminobenzamide group is expected to become a more promising alternative to hydroxamic acid. In fact, o-aminobenzamide-based dual inhibitors of HDAC with different chemical structures have been extensively prepared and reported with synergistic and enhanced anti-tumor effects. In this work, we first time reviewed the rational design, molecular docking, inhibitory activities and potential application of o-aminobenzamide-based HDAC inhibitors with dual targeting capabilities in cancer therapy, which might provide a reference for developing new and more effective anticancer drugs.

Evodiamine impairs HIF1A histone lactylation to inhibit Sema3A-mediated angiogenesis and PD-L1 by inducing ferroptosis in prostate cancer

Prostate cancer (PCa) is among the most commonly diagnosed solid cancers in male adults. However, most anti-angiogenic therapies and immunotherapies fail to achieve durable remission in advanced PCa. Integrative analysis indicated that Sema3A was negatively correlated with the pathological malignancy and was involved in angiogenesis, cell adhesion, and immune infiltrates in PCa. Sema3A significantly inhibited vascular endothelial growth factor (VEGFA)-induced colony formation, cell proliferation, and PD-L1 expression in PCa cells. Network pharmacological analysis demonstrated that evodiamine, a natural alkaloid compound derived from Evodiae fructus fruits, might regulate Sema3A, lipid metabolism, and monocarboxylic acid transport signaling of PCa. Evodiamine evidently inhibited PCa cell viability in a time-dose-dependent manner. Furthermore, evodiamine impaired angiogenesis by increasing Sema3A expression, and induced ferroptosis by reducing glutathione peroxidase 4 (GPX4) expression, which could be reversed by the ferroptosis blocker ferrostatin-1. Lactate treatment increased hypoxia-inducible factor (HIF)-1α and PD-L1 expressions while restricting Sema3A expression in PCa cells, which could be reversed by silencing monocarboxylate transporter 4 (MCT4) expression. Moreover, evodiamine markedly blocked lactate-induced angiogenesis by restricting histone lactylation and expression of HIF1A in PCa cells, further enhancing Sema3A transcription while inhibiting that of PD-L1. In vivo, evodiamine remarkably inhibited PCa xenograft growth in nude mice, repressing expressions of HIF1α, H3K18la, GPX4, PD-L1, and proliferation, while hindering angiogenesis by increasing Sema3A expression. Therefore, Sema3A represents an essential antineoplastic biomarker, while evodiamine may act as a metabolic-epigenetic modulator, as well as a promising agent in either PCa anti-angiogenic therapy or immunotherapy.

Single Inhibitors versus Dual Inhibitors: Role of HDAC in Cancer

Due to the multimodal character of cancer, inhibition of two targets simultaneously by a single molecule is a beneficial and effective approach against cancer. Histone deacetylase (HDAC) was widely investigated as a novel category of anticancer drug targets due to its crucial role in various biological processes like cell-proliferation, metastasis, and apoptosis. Numerous HDAC inhibitors such as vorinostat and panobinostat are clinically approved but have limited usage due to their low efficacy, nonselectivity, drug resistance, and toxicity. Therefore, HDACs with a dual targeting ability have attracted great attention. The strategy of combining a HDAC inhibitor with other antitumor agents has been proved advantageous for combating the nonselectivity and drug resistivity problems associated with single-target drugs. Henceforth, we have highlighted dual-targeting inhibitors to target HDAC along with topoisomerase, receptor tyrosine kinase inhibitors, and the zeste homolog 2 enzyme. Our Review mainly focuses on the impact of the substituent effect along with the linker variation of well-known HDAC-inhibitor-conjugated anticancer drugs.

Design, synthesis, and biological evaluation of novel HDAC inhibitors with a 3-(benzazol-2-yl)quinoxaline framework

A series of novel histone deacetylase (HDAC) inhibitors derived from 3-(benzazol-2-yl)quinoxaline derivatives were designed and synthesized by a pharmacophore fusion strategy. In vitro results showed that most of the synthesized compounds exhibited good anti-proliferative activity. Among them, compound 10c showed the most potent cytotoxicity, especially in HCT-116 cells with an IC50 value of 0.91 μM much superior to Vorinostat (5.66 μM). 10c was also found to induce cell apoptosis, arrest the cell cycle at G2/M phase, induce the generation of reactive oxygen species and inhibit cell invasion and migration in HCT-116 cells. Further studies revealed that 10c could up-regulate the acetylation levels of H3 and α-tubulin, exhibit significant Topo I inhibition and induce the release of related apoptotic biomarkers. These results highlight the great potential of 10c to become a promising anti-cancer HDAC inhibitor.

Design, synthesis and biological evaluation of dual Topo II/HDAC inhibitors bearing pyrimido[5,4-b]indole and pyrazolo[3,4-d]pyrimidine motifs

Both topoisomerase II (Topo II) and histone deacetylase (HDAC) are important therapeutic targets for cancer. In this study, two series of novel compounds containing pyrimido[5,4-b]indole and pyrazolo[3,4-d]pyrimidine motifs were designed and synthesized as dual Topo II/HDAC inhibitors. MTT assay indicated that all the compounds displayed potential antiproliferative activity against three cancer cell lines (MGC-803, MCF-7 and U937) and low cytotoxicity on normal cell line (3T3). In the enzyme activity inhibition experiments, compounds 7d and 8d exhibited excellent dual inhibitory activities against Topo II and HDAC. Cleavage reaction assay showed that 7d was a Topo II poison, which was consistent with the docking results. Further experimental results revealed that compounds 7d and 8d could promote apoptosis and significantly inhibit the migration in MCF-7 cells. Molecular docking showed that compounds 7d and 8d bind Topo II and HDAC at the active sites. Molecular dynamics simulation showed that 7d can stably bind to Topo II and HDAC.

Design and Synthesis of Triazole-Containing HDAC Inhibitors That Induce Antitumor Effects and Immune Response

Histone deacetylase (HDAC) is an epigenetic antitumor drug target, but most existing HDAC inhibitors show limited antitumor activity and their use is often accompanied by serious adverse effects. To overcome these problems, we designed and synthesized a series of triazole-containing compounds as novel HDAC inhibitors. Among them, compound 19h exhibited potent and selective inhibition of HDAC1, with good antiproliferative activity in vitro and an excellent pharmacokinetic profile. Compound 19h significantly inhibited the growth of human tumor xenografts in nude mice and murine tumor growth in immune-competent mice bearing MC38 colon cancer. In the MC38 model, 19h increased the ratio of splenic CD4⁺ T effector cells and promoted complete tumor regression in 5/6 animals when combined with the mPD-1 antibody. These results suggested that selective class I HDAC inhibitors exert direct tumor growth inhibition and indirect immune cell-mediated antitumor effects and are synergistic with immune checkpoint inhibitors.

Combination of DNA Damage, Autophagy, and ERK Inhibition: Novel Evodiamine-Inspired Multi-Action Pt(IV) Prodrugs with High-Efficiency and Low-Toxicity Antitumor Activity

Exploring multi-targeting chemotherapeutants with advantages over single-targeting agents and drug combinations is of great significance in drug discovery. Herein, we employed phytogenic evodiamine (EVO) and conventional Pt(II) drugs to design and synthesize multi-target EVO-Pt(IV) anticancer prodrugs (4-14). Among them, compound 10 exhibited a 118-fold enhancement in the IC₅₀ value compared to cisplatin and low toxicity to normal cells. Further studies proved that 10 significantly enhanced intracellular Pt accumulation and DNA damage, perturbed mitochondrial membrane potential, inhibited cell migration and invasion, upregulated reactive oxygen species levels, and induced apoptosis and autophagic cell death. Molecular docking assay revealed that 10 fits perfectly into the extracellular signal-regulated protein kinase (ERK)-1 pocket, which was verified to produce profound ERK suppression. Most strikingly, compound 10 exhibited superior in vivo antitumor efficiency and effectively attenuated systemic toxicity. Our results emphasize that functionalizing platinum drugs with the multi-target EVO could generate synergistically excellent anticancer activity with low toxicity and decreased resistance, which may represent a brand-new cancer therapy modality.

Natural product evodiamine-inspired medicinal chemistry: Anticancer activity, structural optimization and structure-activity relationship

It is a well-known phenomenon that natural products can serve as powerful drug leads to generate new molecular entities with novel therapeutic utility. Evodiamine (Evo), a major alkaloid component in traditional Chinese medicine Evodiae Fructus, is considered a desirable lead scaffold as its multifunctional pharmacological properties. Although natural Evo has suboptimal biological activity, poor pharmacokinetics, low water solubility, and chemical instability, medicinal chemists have succeeded in producing synthetic analogs that overshadow the deficiency of Evo in terms of further clinical application. Recently, several reviews on the synthesis, structural modification, mechanism pharmacological actions, structure-activity relationship (SAR) of Evo have been published, while few reviews that incorporates intensive structural basis and extensive SAR are reported. The purpose of this article is to review the structural basis, anti-cancer activities, and mechanisms of Evo and its derivatives. Emphasis will be placed on the optimizing strategies to improve the anticancer activities, such as structural modifications, pharmacophore combination and drug delivery systems. The current review would benefit further structural modifications of Evo to discover novel anticancer drugs.

Targeting cancer stem cells and signalling pathways through phytochemicals: A promising approach against colorectal cancer

BACKGROUND

Cancer stem cells (CSCs) are strongly associated with high tumourigenicity, chemotherapy or radiotherapy resistance, and metastasis and recurrence, particularly in colorectal cancer (CRC). Therefore, targeting CSCs may be a promising approach. Recently, discovery and research on phytochemicals that effectively target colorectal CSCs have been gaining popularity because of their broad safety profile and multi-target and multi-pathway modes of action.

PURPOSE

This review aimed to elucidate and summarise the effects and mechanisms of phytochemicals with potential anti-CSC agents that could contribute to the better management of CRC.

METHODS

We reviewed PubMed, EMBASE, Web of Science, Ovid, ScienceDirect and China National Knowledge Infrastructure databases from the original publication date to March 2022 to review the mechanisms by which phytochemicals inhibit CRC progression by targeting CSCs and their key signalling pathways. Phytochemicals were classified and summarised based on the mechanisms of action.

RESULTS

We observed that phytochemicals could affect the biological properties of colorectal CSCs. Phytochemicals significantly inhibit self-renewal, migration, invasion, colony formation, and chemoresistance and induce apoptosis and differentiation of CSCs by regulating the Wnt/β-catenin pathway (e.g., diallyl trisulfide and genistein), the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin pathway (e.g., caffeic acid and piperlongumine), the neurogenic locus notch homolog protein pathway (e.g., honokiol, quercetin, and α-mangostin), the Janus kinase-signal transducer and activator of transcription pathway (e.g., curcumin, morin, and ursolic acid), and other key signalling pathways. It is worth noting that several phytochemicals, such as resveratrol, silibinin, evodiamine, and thymoquinone, highlight multi-target and multi-pathway effects in restraining the malignant biological behaviour of CSCs.

CONCLUSIONS

This review demonstrates the potential of targeted therapies for colorectal CSCs using phytochemicals. Phytochemicals could serve as novel therapeutic agents for CRC and aid in drug development.

The emerging roles of HDACs and their therapeutic implications in cancer

Deregulation of protein post-translational modifications is intensively involved in the etiology of diseases, including degenerative diseases, inflammatory injuries, and cancers. Acetylation is one of the most common post-translational modifications of proteins, and the acetylation levels are controlled by two mutually antagonistic enzyme families, histone acetyl transferases (HATs) and histone deacetylases (HDACs). HATs loosen the chromatin structure by neutralizing the positive charge of lysine residues of histones; whereas HDACs deacetylate certain histones, thus inhibiting gene transcription. Compared with HATs, HDACs have been more intensively studied, particularly regarding their clinical significance. HDACs extensively participate in the regulation of proliferation, migration, angiogenesis, immune escape, and therapeutic resistance of cancer cells, thus emerging as critical targets for clinical cancer therapy. Compared to HATs, inhibitors of HDAC have been clinically used for cancer treatment. Here, we enumerate and integratethe mechanisms of HDAC family members in tumorigenesis and cancer progression, and address the new and exciting therapeutic implications of single or combined HDAC inhibitor (HDACi) treatment.

MicroRNA-147a Targets SLC40A1 to Induce Ferroptosis in Human Glioblastoma

Objective. Glioblastoma is one of the most common malignant tumors in the brain, and these glioblastoma patients have very poor prognosis. Ferroptosis is involved in the progression of various tumors, including the glioblastoma. This study aims to determine the involvement of microRNA (miR)-147a in regulating ferroptosis of glioblastoma in vitro. Methods. Human glioblastoma cell lines were transfected with the inhibitor, mimic and matched negative controls of miR-147a in the presence or absence of ferroptotic inducers. To knock down the endogenous solute carrier family 40 member 1 (SLC40A1), cells were transfected with the small interfering RNA against SLC40A1. In addition, cells with or without the miR-147a mimic treatment were also incubated with temozolomide (TMZ) to investigate whether miR-147a overexpression could sensitize human glioblastoma cells to TMZ chemotherapy in vitro. Results. We found that miR-147a level was decreased in human glioblastoma tissues and cell lines and that the miR-147a mimic significantly suppressed the growth of glioblastoma cells in vitro. In addition, miR-147a expression was elevated in human glioblastoma cells upon erastin or RSL3 stimulation. Treatment with the miR-147a mimic significantly induced ferroptosis of glioblastoma cells, and the ferroptotic inhibitors could block the miR-147a mimic-mediated tumor suppression in vitro. Conversely, the miR-147a inhibitor prevented erastin- or RSL3-induced ferroptosis and increased the viability of glioblastoma cells in vitro. Mechanistically, we determined that miR-147a directly bound to the 3 $\prime$ -untranslated region of SLC40A1 and inhibited SLC40A1-mediated iron export, thereby facilitating iron overload, lipid peroxidation, and ferroptosis. Furthermore, miR-147a mimic-treated human glioblastoma cells exhibited higher sensitivity to TMZ chemotherapy than those treated with the mimic control in vitro. Conclusion. We for the first time determine that miR-147a targets SLC40A1 to induce ferroptosis in human glioblastoma in vitro.

Discovery of novel bis-evodiamine derivatives with potent antitumor activity

Inspired by antitumor natural product evodiamine, a series of novel bis-evodiamine derivatives were designed and synthesized, which showed potent antitumor activity. In particular, compound 13b effectively inhibited the proliferation and migration of HCT116 cells. Further mechanism studies revealed that compound 13b acted by inducing HCT116 cell apoptosis and arresting the cell cycle at the G2/M phase. Thus, compound 13b represents a promising lead compound for the discovery of novel antitumor agents.

Homobivalent, Trivalent, and Covalent PROTACs: Emerging Strategies for Protein Degradation

Proteolysis-targeting chimeras (PROTACs) is a fast-growing technology providing many strengths over inhibition of protein activity directly and is attracting increasing interest in new drug discovery and development. However, efficiently identifying potent and drug-like degraders is still challenging in the development of PROTACs. Complementary to traditional PROTACs, several emerging types of PROTACs, such as homobivalent PROTACs based on two E3 ligases (e.g., CRBN, VHL, MDM2, TRIM24), chemical- or biological-based trivalent/multitargeted PROTACs, and covalent PROTACs, are rising for targeted protein degradation. These new types of PROTACs have several advantages over the traditional PROTACs including high selectivity, low toxicity, better therapeutic effects, and so on. In this perspective, we will summarize the latest development of representative PROTACs focusing on research mainly in past 10 years and discuss their advantages and disadvantages. Moreover, the outlook and perspectives on the associated challenges and future directions will be provided.

Design, synthesis and bioactivity evaluation of favorable evodiamine derivative scaffold for developing cancer therapy

Natural product evodiamine is one of the most privileged scaffolds in drug discovery and is suitable for derivatization, which can be conducted quickly for structure optimization and structure-activity relationship research. In this work, a comprehensive SAR study on evodiamine scaffold with N14-3'-fluorophenyl substituted was completed, and compounds with high anti-tumor activity and good inhibitory effect on Top1 and Top2 were screened out. Tested evodiamine derivatives exhibited excellent broad-spectrum anti-tumor activity. Among them, compound 8b revealed 55.15% and 55.50% inhibition for Top1 and Top2 at 25 μM, as well as 0.16 and 0.13 μM IC₅₀ value for MGC-803 and SGC-7901 cells, respectively; compound 9a revealed 70.50% and 71.81% inhibition for Top1 and Top2 at 25 μM, as well as 0.22 and 0.27 μM IC₅₀ value for MGC-803 and SGC-7901 cells, respectively. The further biological evaluation showed that they could functionally induce apoptosis, significantly arrest the cell cycle at the G2/M phase, and markedly inhibit cell proliferation, migration and invasion. In addition, compound 9a performed a tumor inhibitory rate of 36.35% and showed no apparent toxicity in vivo. Overall, these optimized protocols will advance the progression of cancer chemotherapy and can be used to expand the options for screening therapeutic cancer drugs.

Design, Synthesis, and Biological Evaluation of Novel Evodiamine Derivatives as Potential Antihepatocellular Carcinoma Agents

Evodiamine has many biological activities. Herein, we synthesize 23 disubstituted derivatives of N14-phenyl or the E-ring of evodiamine and conduct systematic structure-activity relationship studies. In vitro antiproliferative activity indicated that compounds F-3 and F-4 dramatically inhibited the proliferation of Huh7 (IC₅₀ = 0.05 or 0.04 μM, respectively) and SK-Hep-1 (IC₅₀ = 0.07 or 0.06 μM, respectively) cells. Furthermore, compounds F-3 and F-4 could double inhibit topoisomerases I and II, inhibit invasion and migration, block the cell cycle to the G2/M stage, and induce apoptosis as well. Additionally, compounds F-3 and F-4 could also inhibit the activation of HSC-T6 and reduce the secretion of collagen type I to slow down the progression of liver fibrosis. Most importantly, compound F-4 (TGI = 60.36%) inhibited tumor growth more significantly than the positive drug sorafenib. To sum up, compound F-4 has excellent potential as a strong candidate for the therapy of hepatocellular carcinoma.

Dual-acting antitumor agents targeting the A2A adenosine receptor and histone deacetylases: Design and synthesis of 4-(furan-2-yl)-1H-pyrazolo[3,4-d]pyrimidin-6-amine derivatives

Based on its inhibition by antagonists, the A_2A adenosine receptor (A_2AAR) has attracted attention as an anti-tumor drug target; however, in preclinical models and clinical trials, A_2AAR antagonists have so far shown only limited efficacy as standalone therapies. The design of dual-acting compounds, targeting the A_2AAR and histone deacetylases (HDACs), is used here as an approach to the discovery of novel and more potent antitumor agents. Based on the core structures of the A_2AAR antagonists V-2006 and CPI-444, novel 4-(furan-2-yl)-1H-pyrazolo[3,4-d]pyrimidin-6-amine derivatives were designed as such dual-acting compounds. The binding affinities for A_2AAR of all the new compounds were tested, and their HDAC inhibitory activity was evaluated. Compounds with balanced A_2AAR antagonism and HDAC inhibition were tested for their in vitro anti-proliferative activity and pharmacokinetic properties. One of the compounds, 14c (4-(2-(6-Amino-4-(furan-2-yl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl)ethyl)-N-(2-amino-phenyl)benzamide) showed an overall favorable pharmacokinetic profile; in the mouse MC38 xenograft model, it showed potent anti-tumor effects with inhibition rates of 44% (90 mg/kg, po, bid) and 85% (60 mg/kg, ip, bid), respectively.

Evodiamine-Inspired Topoisomerase-Histone Deacetylase Dual Inhibitors: Novel Orally Active Antitumor Agents for Leukemia Therapy

On the basis of the synergism of topoisomerase (Top) and histone deacetylase (HDAC) inhibitors in antitumor therapy, a series of novel Top/HDAC dual inhibitors were designed and synthesized by the pharmacophore fusion strategy. After systematic structure-activity relationship studies, lead compound 16j was identified to simultaneously inhibit both Top and HDAC with good potency, which showed potent antiproliferative activities with a broad spectrum. Mechanistic studies indicated that compound 16j efficiently induced apoptosis with S cell-cycle arrest in HEL cancer cells. It was orally active in HEL xenograft models and exhibited excellent in vivo antitumor efficacy (TGI = 68.5%; 10 mg/kg). Altogether, this work highlights the therapeutic potential of evodiamine-inspired Top/HDAC dual inhibitors and provides a valuable lead compound for the development of novel antitumor agents for leukemia therapy.

Novel biphenyl-based scaffold as potent and selective histone deacetylase 6 (HDAC6) inhibitors: Identification, development and pharmacological evaluation

A series of novel biphenyl-based scaffold derivatives were identified as selective histone deacetylase 6 (HDAC6) inhibitors through an in-house compound library screening approach. The biological evaluation indicated that most of target compounds exhibited moderate to good inhibitory activity and selectivity against HDAC6. Especially, compound C10 was identified as a potent and highly selective HDACs inhibitor, with HDAC1 IC₅₀ value of 3600 nM, HDAC6 IC₅₀ value of 23 nM, and the HDAC1/6 selectivity index of 157. Moreover, C10 displayed robust anti-proliferative activity, induced cancer cells apoptosis, increased the level of acetylated α-tubulin and inhibited cancer cells migration in vitro. C10 showed significant antitumor efficacy (TGI: 75%) in CT26 colon carcinoma xenograft model in mice with no considerable toxicity in vivo. More importantly, C10 could also activate antitumor immunity so as to synergistically exert antitumor effects in vivo. Overall, our findings have provided a new avenue for design, development and investigation into the mechanism underlying the antitumor efficacy of selective HDAC6 inhibitors.

MicroRNA‐495‐3p diminishes doxorubicin‐induced cardiotoxicity through activating AKT

Doxorubicin (Dox) is a broad‐spectrum antitumour agent; however, its clinical application is impeded due to the cumulative cardiotoxicity. The present study aims to investigate the role and underlying mechanisms of microRNA‐495‐3p (miR‐495‐3p) in Dox‐induced cardiotoxicity. Herein, we found that cardiac miR‐495‐3p expression was significantly decreased in Dox‐treated hearts, and that the miR‐495‐3p agomir could prevent oxidative stress, cell apoptosis, cardiac mass loss, fibrosis and cardiac dysfunction upon Dox stimulation. In contrast, the miR‐495‐3p antagomir dramatically aggravated Dox‐induced cardiotoxicity in mice. Besides, we found that the miR‐495‐3p agomir attenuated, while the miR‐495‐3p antagomir exacerbated Dox‐induced oxidative stress and cellular injury in vitro. Mechanistically, we demonstrated that miR‐495‐3p directly bound to the 3′‐untranslational region of phosphate and tension homology deleted on chromosome ten (PTEN), downregulated PTEN expression and subsequently activated protein kinase B (PKB/AKT) pathway, and that PTEN overexpression or AKT inhibition completely abolished the cardioprotective effects of the miR‐495‐3p agomir. Our study for the first time identify miR‐495‐3p as an endogenous protectant against Dox‐induced cardiotoxicity through activating AKT pathway in vivo and in vitro.

The Synthesis, Structural Modification and Mode of Anticancer Action of Evodiamine: a review

BACKGROUND

Finding novel antitumor reagents from naturally occurring alkaloids is a widely accepted strategy. Evodiamine, a tryptamine indole alkaloid isolated from Evodia rutaecarpa, has a wide range of biological activities, such as antitumor, anti-inflammation, and anti-bacteria. Hence, research works on the structural modification of evodiamine will facilitate the discovery of new antitumor drugs.

OBJECTIVE

The recent advances in the synthesis of evodiamine, and studies on the drug design, biological activities, and structure-activity-relationships of its derivatives, published in patents and primary literatures, are reviewed in this paper.

METHODS

The literatures, including patents and follow-up research papers from 2015 to 2020, related to evodiamine is searched in the Scifinder, PubMed, Espacenet, China National Knowledge Infrastructure (CNKI), and Wanfang databases. The key words are evodiamine, synthesis, modification, anticancer, mechanism.

RESULTS

The synthesis of evodiamine are summarized. Then, structural modifications of evodiamine are described, and the possible modes of actions are discussed.

CONCLUSION

Evodiamine has a 6/5/6/6/6 ring system, and the structural modifications are focused on ring A, D, E, C5, N-13, and N-14. Some compounds show promising anticancer potentials and warrant further study.

Discovery of Novel Polycyclic Heterocyclic Derivatives from Evodiamine for the Potential Treatment of Triple-Negative Breast Cancer

Evodiamine (Evo) is a quinazolinocarboline alkaloid found in Evodia rutaecarpa and exhibits moderate antiproliferative activity. Herein, we report using a scaffold-hopping approach to identify a series of novel polycyclic heterocyclic derivatives based on Evo as the topoisomerase I (Top1) inhibitor for the treatment of triple-negative breast cancer (TNBC), which is an aggressive subtype of breast cancer with limited treatment options. The most potent compound 7f inhibited cell growth in a human breast carcinoma cell line (MDA-MB-231) with an IC₅₀ value of 0.36 μM. Further studies revealed that Top1 was the target of 7f, which directly induced irreversible Top1-DNA covalent complex formation or induced an oxidative DNA lesion through an indirect mechanism mediated by reactive oxygen species. More importantly, in vivo studies showed that 7f exhibited potent antitumor activity in a TNBC-patient-derived tumor xenograft model. These results suggest that compound 7f deserves further investigation as a promising candidate for the treatment of TNBC.

Structure-Based Design of Dual-Acting Compounds Targeting Adenosine A2A Receptor and Histone Deacetylase as Novel Tumor Immunotherapeutic Agents

Adenosine is an immunosuppressive factor in the tumor microenvironment mainly through activation of the A_2A adenosine receptor (A_2AR), which is a mechanism hijacked by tumors to escape immune surveillance. Small-molecule A_2AR antagonists are being evaluated in clinical trials as immunotherapeutic agents, but their efficacy is limited as standalone therapies. To enhance the antitumor effects of A_2AR antagonists, dual-acting compounds incorporating A_2AR antagonism and histone deacetylase (HDAC) inhibitory actions were designed and synthesized, based on co-crystal structures of A_2AR. Compound 24e (IHCH-3064) exhibited potent binding to A_2AR (K_i = 2.2 nM) and selective inhibition of HDAC1 (IC₅₀ = 80.2 nM), with good antiproliferative activity against tumor cell lines in vitro. Intraperitoneal administration of 24e (60 mg/kg, bid) inhibited mouse MC38 tumor growth with a tumor growth inhibition rate of 95.3%. These results showed that dual-acting compounds targeting A_2AR and HDAC are potentially immunotherapeutic agents that are worth further exploring.

Design, synthesis and bioactivity study of evodiamine derivatives as multifunctional agents for the treatment of hepatocellular carcinoma

Topoisomerase has been found extremely high level of expression in hepatocellular carcinoma (HCC) and proven to promote the proliferation and survival of HCC. Cancer-associated fibroblasts (CAFs) as a kind of key reactive stromal cell that abundantly present in the microenvironment of HCC, could enhance the metastatic ability and drug resistance of HCC. Therefore, developing new drugs that address the above conundrums would be of the upmost significant in the fight against HCC. Evodiamine, as a multi-target natural product, has been found to exert various biological activities such as anti-cancer and anti-hepatic fibrosis via blocking topoisomerase, NF-κB, TGF-β/HGF, and Smad2/3. Inspired by these facts, 15 evodiamine derivatives were designed and synthesized for HCC treatment by simultaneously targeting Topo I and CAFs. Most of them displayed preferable anti-HCC activities on three HCC cell lines and low cytotoxicity on one normal hepatic cell. In particular, compound 8 showed the best inhibitory effect on HCC cell lines and a good inhibition on Topo I in vitro. Meanwhile, it also induced obvious G₂/M arrest and apoptosis, and significantly decreased the migration and invasion capacity of HCC cells. In addition, compound 8 down-regulated the expression of type I collagen in the activated HSC-T6 cells, and induced the apoptosis of activated HSC-T6 cells. In vivo studies demonstrated that compound 8 markedly decreased the volume and weight of tumor (TGI = 40.53%). In vitro and in vivo studies showed that its effects were superior to those of evodiamine. This preliminary attempt may provide a promising strategy for developing anti-HCC lead compounds taking effect through simultaneous inhibition on Topo I and CAFs.

Targeting BMI-1-mediated epithelial-mesenchymal transition to inhibit colorectal cancer liver metastasis

Liver is the most common metastatic site for colorectal cancer (CRC), there is no satisfied approach to treat CRC liver metastasis (CRCLM). Here, we investigated the role of a polycomb protein BMI-1 in CRCLM. Immunohistochemical analysis showed that BMI-1 expression in liver metastases was upregulated and associated with T4 stage, invasion depth and right-sided primary tumor. Knockdown BMI-1 in high metastatic HCT116 and LOVO cells repressed the migratory/invasive phenotype and reversed epithelial-mesenchymal transition (EMT), while BMI-1 overexpression in low metastatic Ls174T and DLD1 cells enhanced invasiveness and EMT. The effects of BMI-1 in CRC cells were related to upregulating snail via AKT/GSK-3β pathway. Furthermore, knockdown BMI-1 in HCT116 and LOVO cells reduced CRCLM using experimental liver metastasis mice model. Meanwhile, BMI-1 overexpression in Ls174T and DLD1 significantly increased CRCLM. Moreover, sodium butyrate, a histone deacetylase and BMI-1 inhibitor, reduced HCT116 and LOVO liver metastasis in immunodeficient mice. Our results suggest that BMI-1 is a major regulator of CRCLM and provide a potent molecular target for CRCLM treatment.

Evodiamine alleviates lipopolysaccharide-induced pulmonary inflammation and fibrosis by activating apelin pathway

Inflammation can cause a series of inflammatory lung disease, which seriously endangers human health. Pulmonary fibrosis is a kind of inflammatory disease with end-stage lung pathological changes. It has complicated and unknown pathogenesis and is still lack of effective therapeutic drugs. LPS-induced inflammation is a common feature of many infectious inflammations such as pneumonia, bacteremia, glomerulonephritis, etc. Evodiamine, one of the main components of Evodia rutaecarpa, is an alkaloid with excellent antiinflammatory effects. In this study, we evaluated the protective capacities of evodiamine on LPS-induced inflammatory damages in vitro and in vivo. MTT method, flow cytometry, immunofluorescence, and other methods were used for in vitro study to determine the protective capacities of evodiamine. The results suggest that evodiamine can protect murine macrophages from the LPS-nigericin-induced damages by (a) inhibiting cellular apoptosis, (b) inhibiting inflammatory cytokines releasing, and (c) activating the apelin pathway. We also used the exogenous apelin-13 peptide co-cultured with LPS-nigericin in RAW264.7 cells and found that apelin-13 contributes to protecting the effects of evodiamine. In vivo, the ELISA method and immunohistochemistry were used to examine inflammatory cytokines, apelin, and histological changes. BALB/c mice were exposed to LPS and subsequent administration of evodiamine （p.o.）for some time, the results of the alveolar lavage fluid and the tissue slices showed that evodiamine treatment alleviated the pulmonary inflammation and fibrosis, stimulated apelin expression and inhibited the inflammatory cytokines. These results provide a basis for the protective effect and mechanism of evodiamine in LPS-induced inflammation and suggest that it might be potential therapeutics in human pulmonary infections.

CAP rigidification of MS-275 and chidamide leads to enhanced antiproliferative effects mediated through HDAC1, 2 and tubulin polymerization inhibition

The study focuses on the prudent design and synthesis of anilide type class I HDAC inhibitors employing a functionalized pyrrolo[2,3-d]pyrimidine skeleton as the surface recognition part. Utilization of the bicyclic aromatic ring to fabricate the target compounds was envisioned to confer rigidity to the chemical architecture of MS-275 and chidamide. In-vitro enzymatic and cellular assays led to the identification of compound 7 as a potent inhibitor of HDAC1 and 2 isoform that exerted substantial cell growth inhibitory effects against human breast MDA-MB-231, cervical HeLa, breast MDA-MB-468, colorectal DLD1, and colorectal HCT116 cell lines with an IC₅₀ values of 0.05-0.47 μM, better than MS-275 and chidamide. In addition, the anilide 7 was also endowed with a superior antiproliferative profile than MS275 and chidamide towards the human cutaneous T cell lymphoma (HH and HuT78), leukemia (HL60 and KG-1), and HDACi sensitive/resistant gastric cell lines (YCC11 and YCC3/7). Exhaustive exploration of the construct 7 confirmed it to be a microtubule-targeting agent that could trigger the cell-cycle arrest in mitosis. In pursuit of extracting the benefits of evidenced microtubule-destabilizing activity of the anilide 7, it was further evaluated against non-small-cell lung cancer cell lines as well as the multiple-drug resistant uterine cancer cell line (MES-SA/Dx5) and overwhelmingly positive results in context of inhibitory effects were attained. Furthermore, molecular modelling studies were performed and some key interactions of the anilide 7 with the amino acid residues of the active site of HDAC1 isoform and tubulin were figured out.

Bifunctional HDAC Therapeutics: One Drug to Rule Them All?

Histone deacetylase (HDAC) enzymes play crucial roles in epigenetic gene expression and are an attractive therapeutic target. Five HDAC inhibitors have been approved for cancer treatment to date, however, clinical applications have been limited due to poor single-agent drug efficacy and side effects associated with a lack of HDAC isoform or complex selectivity. An emerging strategy aiming to address these limitations is the development of bifunctional HDAC therapeutics-single molecules comprising a HDAC inhibitor conjugated to another specificity targeting moiety. This review summarises the recent advancements in novel types of dual-targeting HDAC modulators, including proteolysis-targeting chimeras (PROTACs), with a focus on HDAC isoform and complex selectivity, and the future potential of such bifunctional molecules in achieving enhanced drug efficacy and therapeutic benefits in treating disease.