Targeting NEDD8-activating enzyme for cancer therapy: developments, clinical trials, challenges and future research directions.

NEDDylation, a post-translational modification through three-step enzymatic cascades, plays crucial roles in the regulation of diverse biological processes. NEDD8-activating enzyme (NAE) as the only activation enzyme in the NEDDylation modification has become an attractive target to develop anticancer drugs. To date, numerous inhibitors or agonists targeting NAE have been developed. Among them, covalent NAE inhibitors such as MLN4924 and TAS4464 currently entered into clinical trials for cancer therapy, particularly for hematological tumors. This review explains the relationships between NEDDylation and cancers, structural characteristics of NAE and multistep mechanisms of NEDD8 activation by NAE. In addition, the potential approaches to discover NAE inhibitors and detailed pharmacological mechanisms of NAE inhibitors in the clinical stage are explored in depth. Importantly, we reasonably investigate the challenges of NAE inhibitors for cancer therapy and possible development directions of NAE-targeting drugs in the future.

Synthesis of S-2-phenylchromane Derivatives and Evaluation of the Antiproliferative Properties as Apoptosis Inducers in Cancer Cell Lines.

BACKGROUND: Cancer remains one of the major health issues globally, where chemotherapy forms the main treatment mode for different types of cancers. Due to cancer cell ability to develop resistance, decreased clinical effectiveness of anticancer drugs can occur. Therefore, the need to synthesize novel antitumor drugs remains important. OBJECTIVE: The aim of our work consisted of synthesizing S-2-phenylchromane derivatives containing the tertiary amide or 1,2,3-triazole fragments with promising anticancer activity. METHODS: A series of S-2-phenylchromane derivatives were synthesized and evaluated for cytotoxic activity against three selected cancer cell lines (HGC-27 human gastric carcinoma cell line, Huh-7 epithelial-like tumorigenic cells, and A549 adenocarcinomic human alveolar basal epithelial cells) using the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay. Hoechst staining was used to detect the effects of S-2-phenylchromane derivatives on apoptosis. The apoptosis percentages were detected by annexin V-fluoresceine isothiocyanate/propidium iodide (Annexin V-FITC/PI) double staining assay with flow cytometry. Expression levels of apoptosis-related proteins were detected by western blot. RESULTS: Cell line A549, consisting of adenocarcinomic human alveolar basal epithelial cells, displayed the highest sensitivity to the S-2-phenylchromane derivatives. Among these compounds, E2 showed the most potent antiproliferative activity against A549 cells with an IC50 value of 5.60 µM. Hoechst staining and flow cytometry analysis revealed apoptosis in A549 cells by compound E2. In addition, activation of the expression levels of caspase-3, caspase-7, and their substrate poly (ADP-ribose) polymerase (PARP) by E2 was detected by western blot. CONCLUSION: In summary, results point towards compound E2, an S-2-phenylchromane derivative, as a potential lead molecule in anticancer agents for human adenocarcinomic alveolar basal cells based on the induction of apoptosis.

Discovery of dual tubulin-NEDDylation inhibitors with antiproliferative activity.

Although various dual-target tubulin inhibitors have been designed and synthesised, no dual tubulin-NEDDylation inhibitors as antiproliferative agents were reported so far. In this work, a series of trimethoxyphenyl analogues as potential dual tubulin-NEDDylation inhibitors were synthesised and evaluated for their antiproliferative activity. Among them, compound C11 exhibited the most potent inhibitory activity with IC50 values of 1.17, 2.48, and 1.47 µM against HepG2, PC3, and MCF7 cells, respectively. In addition, it displayed the potent inhibitory activity against tubulin with an IC50 value of 2.40 µM and obviously inhibited tubulin polymerisation in HepG2 cells. Furthermore, C11 inhibited NEDDylation by a ATP-dependent manner. Molecular docking studies revealed that the methoxy group and dithiocarbamate group of C11 could form hydrogen bonds with residues of tubulin and E1 NEDD8-activating enzyme (NAE). These results suggested that compound C11 was a dual tubulin-NEDDylation inhibitor with antiproliferative activity.

Annual review of LSD1/KDM1A inhibitors in 2020.

Lysine-specific demethylase 1 (LSD1/KDM1A) has emerged as a promising target for the discovery of specific inhibitors as antitumor drugs. Based on the source of compounds, all LSD1 inhibitors in this review are divided into two categories: natural LSD1 inhibitors and synthetic LSD1 inhibitors. This review highlights the research progress of LSD1 inhibitors with the potential to treat cancer covering articles published in 2020. Design strategies, structure-activity relationships, co-crystal structure analysis and action mechanisms are also highlighted.

Discovery of novel indole derivatives that inhibit NEDDylation and MAPK pathways against gastric cancer MGC803 cells.

A series of novel indole derivatives were synthesized and evaluated for their antiproliferative activity against three selected cancer cell lines (MGC803, EC-109 and PC-3). Among these analogues, 2-(5-methoxy-1H-indol-1-yl)-N-(4-methoxybenzyl)-N-(3,4,5-trimethoxyphenyl)acetamide (V7) showed the best inhibitory activity against MGC803 cells with an IC50 value of 1.59 µM. Cellular mechanisms elucidated that V7 inhibited colony formation, induced apoptosis and arrested cell cycle at G2/M phase. Importantly, indole analogue V7 inhibited NEDDylation pathway and MAPK pathway against MGC803 cells.

Ras/Raf/MEK/ERK pathway axis mediated neurotoxicity induced by high-risk pesticide residue-Avermectin.

Pesticide residues have become a healthy threaten of human beings. Among the pesticides, many of them have neurotoxicity. Extracellular Regulated Protein Kinases (ERK) pathway is an important signaling pathway that regulates a variety of downstream progress. In this work, peach (PRUNUS persica) and cherry (PRUNUS cerasus) were sampled from over 300 plantations in China and assessed for the residue risk. In mechanism studies, high-risk pesticide Avermectin showed a high activity inhibiting three neurotoxicity models, SH-SY5Y, PC-12 and SK-N-SH cells. At protein levels, ERK pathway proteins and their downstream proteins were obviously down-regulated. Moreover, the effects of low-dose Avermectin can be accumulated at protein levels in the low-dose long-term chronic toxicology detection.

Discovery of tertiary amide derivatives incorporating benzothiazole moiety as anti-gastric cancer agents in vitro via inhibiting tubulin polymerization and activating the Hippo signaling pathway.

On the basis and continuation of our previous studies on anti-tubulin and anti-gastric cancer agents, novel tertiary amide derivatives incorporating benzothiazole moiety were synthesized and the antiproliferative activity was studied in vitro. Preliminary structure activity relationships (SARs) were explored according to the in vitro antiproliferative activity results. Some of compounds could significantly inhibit the proliferation of three cancer cells (HCT-116, MGC-803 and PC-3 cells) and compound F10 exhibited excellent antiproliferative activity against HCT-116 cells (IC50 = 0.182 µM), MGC-803 cells (IC50 = 0.035 µM), PC-3 cells(IC50 = 2.11 µM) and SGC-7901 cells (IC50 = 0.049 µM). Compound F10 effectively inhibited tubulin polymerization (IC50 = 1.9 µM) and bound to colchicine binding site of tubulin. Molecular docking results suggested compound F10 could bind tightly into the colchicine binding site of ß-tubulin. Moreover, compound F10 could regulate the Hippo/YAP signaling pathway. Compound F10 activated Hippo signaling pathway from its very beginning MST1/2, as the result of Hippo cascade activation YAP were inhibited. And then it led to a decrease of c-Myc and Bcl-2 expression. Further molecular experiments showed that compound F10 arrested at G2/M phase, inhibited cell colony formatting and induced extrinsic and intrinsic apoptosis in MGC-803 and SGC-7901 cells. Collectively, compound F10 was the first to be reported as a new anticancer agent in vitro via inhibiting tubulin polymerization and activating the Hippo signaling pathway.

Novel piperidine derivatives as colchicine binding site inhibitors induce apoptosis and inhibit epithelial-mesenchymal transition against prostate cancer PC3 cells.

Tubulin polymerisation inhibitors that target colchicine binding site were powerful anticancer agents. Although along the years many colchicine binding site inhibitors (CBSIs) have been reported, few piperidine derivatives were identified as CBSIs. In this regard, we focussed efforts on the piperidine as a promising chemotype to develop potent CBSIs. Herein, novel piperidine derivatives were synthesised and evaluated for their antiproliferative activities. Among them, compound 17a displayed powerful anticancer activity with the IC50 value of 0.81 µM against PC3 cells, which was significantly better than 5-fluorouracil. It could inhibit tubulin polymerisation binding at the colchicine site and inhibit the tumour growth in vitro and in vivo. Further biological studies depicted that 17a suppressed the colony formation, induced apoptosis, and inhibited epithelial-mesenchymal transition against PC3 cells. These results revealed that compound 17a is a promising colchicine binding site inhibitor for the treatment of cancer and it is worthy of further exploitation.

ß-Lactams as promising anticancer agents: Molecular hybrids, structure activity relationships and potential targets.

ß-Lactam, commonly referred as azetidin-2-one, is a multifunctional building block for synthesizing ß-amino ketones, γ-amino alcohols, and other compounds. Besides its well known antibiotic activity, this ring system exhibits a wide range of activities, attracting the attention of researchers. However, the structurally diverse ß-lactam analogues as anticancer agents and their different molecular targets are poorly discussed. The purpose of this review is 3-fold: (1) to explore the molecular hybridization approach to design ß-lactams hybrids as anticancer agents; (2) the structure activity relationship of the most active anticancer ß-lactams and (3) to summarize their antitumor mechanisms.

Antiproliferative benzothiazoles incorporating a trimethoxyphenyl scaffold as novel colchicine site tubulin polymerisation inhibitors.

Tubulin polymerisation inhibitors exhibited an important role in the treatment of patients with prostate cancer. Herein, we reported the medicinal chemistry efforts leading to a new series of benzothiazoles by a bioisosterism approach. Biological testing revealed that compound 12a could significantly inhibit in vitro tubulin polymerisation of a concentration dependent manner, with an IC50 value of 2.87 µM. Immunofluorescence and EBI competition assay investigated that compound 12a effectively inhibited tubulin polymerisation and directly bound to the colchicine-binding site of ß-tubulin in PC3 cells. Docking analysis showed that 12a formed hydrogen bonds with residues Tyr357, Ala247 and Val353 of tubulin. Importantly, it displayed the promising antiproliferative ability against C42B, LNCAP, 22RV1 and PC3 cells with IC50 values of 2.81 µM, 4.31 µM, 2.13 µM and 2.04 µM, respectively. In summary, compound 12a was a novel colchicine site tubulin polymerisation inhibitor with potential to treat prostate cancer.

Discovery of novel tertiary amide derivatives as NEDDylation pathway activators to inhibit the tumor progression in vitro and in vivo.

NEDDylation pathway regulates multiple physiological process, unlike inhibitors, NEDDylation activators are rarely studied. Novel amide derivatives were synthesized and evaluated for antiproliferative activity against MGC803, MCF-7 and PC-3 cells. Among them, Ⅶ-31 displayed the most potent activity with an IC50 value of 94 nmol/L against MGC803 cells. Cellular mechanisms elucidated that Ⅶ-31 inhibited the cell viability, arrested cell cycle at G2/M phase and induced apoptosis via intrinsic and extrinsic pathways against MGC803 cells. In addition, Ⅶ-31 activated NAE1-Ubc12-Cullin1 NEDDylation via interacting with NAE1 directly. Furthermore, the activation of NEDDylation resulted in the degradation of inhibitor of apoptosis proteins (IAPs). Importantly, Ⅶ-31 inhibited tumor growth in xenograft models in vivo without the apparent toxicity. In summary, it is the first time to reveal that Ⅶ-31 deserves consideration for cancer therapy as a NEDDylation activator.

Gartanin is a novel NEDDylation inhibitor for induction of Skp2 degradation, FBXW2 expression, and autophagy.

Gartanin, a 4-prenylated xanthone, has been identified from the purple mangosteen fruit as a potent growth inhibitor of various cancer cell lines, including prostate cancer. However, much of Gartanin's anticancer mechanism remains unknown. We have discovered that Gartanin docked onto the regulatory subunit of the precursor cell-expressed developmentally downregulated 8 (NEDD8)-activating enzyme (NAE) complex and next to the NEDD8 binding complex, which leads to inhibit NEDD8 conjugations to both Cullin1 and Ubc12 in prostate cancer cell lines and Ubc12 NEDDylation in an in vitro assay. The S phase kinase-associated protein (Skp2) and F-box and WD-repeat domain-containing 2 (FBXW2), the NEDD8 family members of E3 ubiqutin ligases, were also downregulated and upregulated by Gartainin, respectively. Knock-down of NEDD8 expression by short harpin (Sh) RNAs blocked or attenuated these effects of Gartainin. Finally, Gartanin demonstrated its ability to inhibit growth of prostate cancer lines via autophagy initiation. Our data support that Gartanin is a naturally occurring NEDDylation inhibitor and deserves further investigation for prostate cancer prevention and treatment.

Discovery of indoline derivatives that inhibit esophageal squamous cell carcinoma growth by Noxa mediated apoptosis.

A series of novel indoline derivatives were synthesized and evaluated for antiproliferative activity against four selected cancer cell lines (Hela, A549, HepG2 and KYSE30). Among them, compound 20 displayed the potent inhibition activity against esophageal cancer cells (Kyse30, Kyse450, Kyse510 and EC109). Cellular mechanism studies in esophageal squamous cell carcinoma (ESCC) cells elucidated compound 20 inhibited cell growths in vitro and in vivo, reduced colony formation, arrested cell cycle at M phase, and induced Noxa-dependent apoptosis in ESCC. Importantly, compound 20 was identified as a novel Noxa mediated apoptosis inducer. These results suggested that compound 20 might be a promising anticancer agent with potential for development of further clinical applications.

Discovery of novel chalcone-dithiocarbamates as ROS-mediated apoptosis inducers by inhibiting catalase.

Novel chalcone-dithiocarbamate hybrids were designed, synthesized and evaluated for antiproliferative activity against selected cancer cell lines (MGC803, MCF7, and PC3). Among these analogues, (E)-2-oxo-2-((4-(3-(3,4,5-trimethoxyphenyl)acryloyl)phenyl)amino)ethyl-4-(2-hydroxyethyl)piperazine-1-carbodithioate (12d) showed the best inhibitory activity against PC3 cells (IC50 = 1.05 µM). Cellular mechanism studies elucidated 12d could inhibit colony formation, arrest cell cycle at G2/M phase and induce DNA damage against PC3 cells. Compound 12d also induced mitochondrial apoptosis by caspase activation, MMP decrease, ROS production and catalase (CAT) inhibition. Importantly, 12d inhibited epithelial-mesenchymal transition (EMT) process by regulating EMT-related proteins (E-cadherin, N-cadherin, Vimentin, MMP2, MMP9). These results indicated that 12d is a promising lead compound and deserves further investigation for prevention and treatment of human prostate cancer.

Molecular diversity of trimethoxyphenyl-1,2,3-triazole hybrids as novel colchicine site tubulin polymerization inhibitors.

Structurally diverse trimethoxyphenyl-1,2,3-triazole hybrids were designed, synthesized and evaluated for their antiproliferative activity against three cancer cell lines (PC3, MGC803 and HepG2). Among them, trimethoxyphenyl-1,2,3-triazole containing the coumarin fragement 19c displayed better antiproliferative activity results with IC50 values from 0.13 µM to 1.74 µM than anticancer drug colchicine. Compound 19c could inhibit MGC803 cell growth and colony formation, induce G2/M phase arrest by down expression of CDK1, and promote apoptosis by regulating DR5 and Bcl-2 family. Moreover, 19c strongly inhibited tubulin polymerization by interacting with the colchicine site.

Identification of osimertinib (AZD9291) as a lysine specific demethylase 1 inhibitor.

Osimertinib (AZD9291) is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that has been approved for the treatment of EGFR-mutated non-small cell lung cancer (NSCLC). In this study, osimertinib was characterized as a LSD1 inhibitor for the first time with an IC50 of 3.98 ±â€¯0.3 µM and showed LSD1 inhibitory effect at cellular level. These findings provide new molecular skeleton for dual inhibitor for LSD1 and EGFR. Osimertinib could serve as a lead compound for further development for anti-NSCLC drug discovery with dual targeting.

Mechanisms of synergistic neurotoxicity induced by two high risk pesticide residues - Chlorpyrifos and Carbofuran via oxidative stress.

Multi-component pesticide residues, especially pesticide residues with synergistic toxicity, are a serious threat to food safety. With risk assessment, we found that Chlorpyrifos (CPF) and Carbofuran (CBF) are 2 pesticide residues with highest risk for Actinidia chinensis planch. The results showed CPF and CBF have a synergistic neurotoxicity on neural cell SK-N-SH. The toxicity was partly depending on oxidative stress (OS) and had effects on cell apoptosis and cell cycle arrest. Furthermore, the toxicity remained on long-term low-dose condition.

Bioactive heterocycles containing a 3,4,5-trimethoxyphenyl fragment exerting potent antiproliferative activity through microtubule destabilization.

Novel bioactive heterocycles containing a 3,4,5-trimethoxyphenyl fragment as antiproliferative agents by targeting tubulin were synthesized and their preliminary structure activity relationships (SARs) were explored. Among all these chemical agents, 2-(Benzo[d]oxazol-2-ylthio)-N-(4-methoxybenzyl)-N-(3,4,5-trimethoxyphenyl)acetamide (4d) exhibited the potent antiproliferative activity against MGC-803 cells with an IC50 value of 0.45 µM by induction of G2/M pahse arrest and cell apoptosis. In addition, 4d could change the membrane potential (ΔΨ) of the mitochondria against MGC-803 cells. Importantly, 4d acted as a novel tubulin polymerization inhibitor binding to colchicine site with an IC50 value of 3.35 µM.

Design, synthesis and preliminary biological evaluation of 5,8-dihydropteridine-6,7-diones that induce apoptosis and suppress cell migration.

Pteridines are an important class of fused heterocycles found in natural products and drug molecules, and have shown diverse biological activities. A focused library of 5,8-dihydropteridine-6,7-dione derivatives were designed and evaluated for their antiproliferative activity against MGC-803, SGC-7901, A549 and PC-3 cancer cell lines. The SARs studies highlighted the importance of the piperazine substituted 5,8-dihydropteridine-6,7-dione frameworks for the activity and revealed essential structural elements. Among these compounds, compound 5n displayed the most potent and broad-spectrum antiproliferative inhibition against the tested cell lines and was sensitive to MGC-803 cell line, slightly more potent than 5-FU. Preliminary mechanistic studies showed that compound 5n could inhibit the colony formation and migration of MGC-803 cells. Besides, flow cytometry analysis showed that compound 5n concentration-dependently induced apoptosis of MGC-803 cells. Our studies suggest that the piperazine substituted 5,8-dihydropteridine-6,7-dione frameworks may be regarded as new chemotypes for designing effective antitumor agents targeting gastric cancer cells.