Discovery of tranylcypromine analogs with an acylhydrazone substituent as LSD1 inactivators: Design,synthesis and their biological evaluation

Lysine specific demethylase 1 (LSD1), the first identified histone demethylase, plays an important role in epigenetic regulation of gene activation and repression, has been reported to be up-regulated and involved in numbers of solid malignant tumors. In this study, we identified a series of phenylalanyl hydrazones based LSD1 inhibitors, and the most potent one, compound 4q, can inactivate LSD1 with IC₅₀?=?91.83?nM. In cellular level, compound 4q can induce the accumulation of CD86 as well as H3K4me2, and inhibit gastric cancer cell proliferation by inactivating LSD1. Our findings indicated that compound 4q may serve as a potential leading compound to target LSD1 overexpressed gastric cancer.     

Design,synthesis and biological activity of 4-(4-benzyloxy)phenoxypiperidines as selective and reversible LSD1 inhibitors

Lysine specific demethylase 1 (LSD1) plays a vital role in epigenetic regulation of gene activation and repression in several human cancers and is recognized as a promising antitumor therapeutic target. In this paper, a series of 4-(4-benzyloxy)phenoxypiperidines were synthesized and evaluated. Among the tested compounds, compound 10d exhibited the potent and reversible inhibitory activity against LSD1 in vitro (IC₅₀ = 4 μM). Molecular docking was conducted to predict its binding mode. Furthermore, 10d displayed it could inhibit migration of HCT-116 colon cancer cells and A549 lung cancer cells. Taken together, 10d deserves further investigation as a hit-to-lead for the treatment of LSD1 associated tumors.     

Optimization of 5-arylidene barbiturates as potent,selective, reversible LSD1 inhibitors for the treatment of acute promyelocytic leukemia

Histone lysine specific demethylase 1 (LSD1) is overexpressed in diverse hematologic disorders and recognized as a promising target for blood medicines. In this study, molecular docking-based virtual screening united with bioevaluation was utilized to identify novel skeleton of 5-arylidene barbiturate as small-molecule inhibitors of LSD1. Among the synthesized derivatives, 12a exhibited reversible and potent inhibition (IC₅₀?=?0.41?μM) and high selectivity over the MAO-A and MAO-B. Notably, 12a strongly induced differentiation effect on acute promyelocytic leukemia NB4 cell line and distinctly escalated the methylation level on histone 3 lysine 4 (H3K4). Our findings indicate that 5-arylidene barbiturate may represent a new skeleton of LSD1 inhibitors and 12a deserve as a promising agent for the further research.     

Bioactivity evaluation of natural product α-mangostin as a novel xanthone-based lysine-specific demethylase 1 inhibitor to against tumor metastasis

Lysine-specific demethylase 1 (LSD1), which has been reported to be overexpressed in several human cancers, has recently emerged as an attractive therapeutic target for treating cancer. To date, almost all the developed LSD1 inhibitors are chemo-synthesized molecules, while α-mangostin is first characterized as xanthone-based natural inhibitor in the current study with IC₅₀ values of 2.81 ± 0.44 μM. Bioactivity study and docking analysis indicated that α-mangostin could inhibit MDA-MB-231 cells migration and evasion through inhibit intracellular LSD1 activity. These findings provides new molecular skeleton for LSD1 inhibitor study and should encourage further modification of α-mangostin to produce more potent LSD1 inhibitors with potential anticancer activity.     

Design,synthesis and in vitro evaluation of stilbene derivatives as novel LSD1 inhibitors for AML therapy

LSD1 is implicated in a number of malignancies and has emerged as an exciting target. As part of our sustained efforts to develop novel reversible LSD1 inhibitors for epigenetic therapy of cancers, in this study, we reported a series of stilbene derivatives and evaluated their LSD1 inhibitory activities, obtaining several compounds as potent LSD1 inhibitors with IC₅₀ values in submicromolar range. Enzyme kinetics studies and SPR assay suggested that compound 8c, the most active LSD1 inhibitor (IC₅₀?=?283?nM), potently inhibited LSD1 in a reversible and FAD competitive manner. Consistent with the kinetics data, molecular docking showed that compound 8c can be well docked into the FAD binding site of LSD1. Flow cytometry analysis showed that compound 8c was capable of up-regulating the expression of the surrogate cellular biomarker CD86 in THP-1 human leukemia cells, suggesting the ability to block LSD1 activity in cells. Compound 8c showed good inhibition against THP-1 and MOLM-13 cells with IC₅₀ values of 5.76 and 8.34?μM, respectively. Moreover, compound 8c significantly inhibited colony formation of THP-1 cells dose dependently.     

Discovery of vanadium complexes bearing tridentate schiff base ligands as novel LSD1 inhibitors

Lysine specific demethylase (LSD1) plays a pivotal role in epigenetic modulation of gene expression. Abberrant expression of LSD1 was associated with the progress and oncogenesis of multiple human cancers. Herein, we report the preliminary anti-LSD1 evaluation of the synthetic vanadium (V) complexes. Among them, complex 2 showed a moderate inhibitory effect against LSD1 with IC₅₀ value of 19.0?μM, as well as good selectivity over MAO-A/B. Complex 2 is the first vanadium based LSD1 inhibitor, which provides a novel scaffold for the development of LSD1 inhibitor.     

Design,synthesis and biological activity of 3-oxoamino-benzenesulfonamides as selective and reversible LSD1 inhibitors

Lysine specific demethylase 1 (LSD1) is a flavin-dependent amine oxidase that selectively removes one or two methyl groups from H3 at Lys4 and is recognized as a promising therapeutic target for cancer and other diseases. Here, a series of 3-oxoamino-benzenesulfonamides were synthesized and evaluated for their inhibitory activity against LSD1. Compounds 7b and 7h showed the most potent inhibition with the IC₅₀ values of 9.5 and 6.9 μM, respectively. Furthermore, the LSD1 inhibition of 7b and 7h were reversible and selective. Docking study presented the possible binding mode between 7b, 7h and the LSD1 active site. Taken together, 3-oxoamino-benzenesulfonamides may represent a new class of reversible LSD1 inhibitors and 7b and 7h were two hit compounds deserved further structural optimization.     

Design,synthesis and biological evaluation of pyrimidine-based derivatives as VEGFR-2 tyrosine kinase inhibitors

Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in tumor angiogenesis, and inhibition of the VEGFR-2 signaling pathway has already become an attractive approach for cancer therapy. In this study, a novel pyrimidine-based derivative 7j was designed as lead compound, and three series of potent VEGFR-2 inhibitors were synthesized and biologically evaluated against A549 and HepG2 cell lines. Compounds 7d, 9s and 13n exhibited superior inhibitory activities against A549 cell with IC₅₀ ranged from 9.19 to 13.17 μM and HepG2 cell with IC₅₀ ranged from 11.94 to 18.21 μM compared to those of Pazopanib (IC₅₀ = 21.18 and 36.66 μM). In addition, molecular docking study was performed to investigate the binding capacity and binding mode between target compounds and VEGFR-2.     

Design,synthesis, and biological evaluation of 4-phenoxyquinoline derivatives as potent c-Met kinase inhibitor

A series of novel 4-phenoxyquinoline derivatives containing 3-oxo-3,4-dihydro-quinoxaline moiety were synthesized and evaluated for their antiproliferative activity against five human cancer cell lines (A549, H460, HT-29, MKN-45 and U87MG) in vitro. Most of the tested compounds exhibited more potent inhibitory activities than the positive control foretinib. Compound 1b, 1s and 1t were further examined for their inhibitory activity against c-Met kinase. The most promising compound 1s (with c-Met IC₅₀ value of 1.42 nM) showed remarkable cytotoxicity against A549, H460, HT-29, MKN45 and U87MG cell lines with IC₅₀ values of 0.39 μM, 0.18 μM, 0.38 μM, 0.81 μM, respectively. Their preliminary structure-activity relationships (SARs) study indicated that the replacement of the aromatic ring with the cyclohexane improved their antiproliferative activity.     

Design,synthesis and biological evaluation of novel 4,5-dihydro-[1,2,4]triazolo[4,3-f]pteridine derivatives as potential BRD4 inhibitors

Recently, diverse kinase inhibitors were reported having interaction with BRD4. It provided a strategy for developing a new structural framework for the next-generation BRD4-selective inhibitors. Starting from PLK1 kinase inhibitor BI-2536, we designed 18 compounds by modifying dihydropteridine core. Compound 23 showed potent BRD4 inhibitory activities with IC₅₀ of 79 nM and no inhibitory activities for PLK1. Cell antiproliferation assay was performed and potent inhibitory activity against MV4;11 with IC₅₀ of 1.53 μM. Cell apoptosis and western blotting indicated compound 23 induced apoptosis by down-regulating c-Myc. These novel selective BRD4 inhibitors provided new lead compounds for further drug development.     

Novel [1,2,4]triazolo[1,5-a]pyrimidine derivatives as potent antitubulin agents: Design,multicomponent synthesis and antiproliferative activities

As restricted CA-4 analogues, a novel series of [1,2,4]triazolo[1,5-a]pyrimidines possessing 3,4,5-trimethoxylphenyl groups has been achieved successfully via an efficient one-pot three-component reaction of 3-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazol-5-amine, 1,3-dicarbonyl compounds and aldehydes. Initial biological evaluation demonstrated some of target compounds displayed potent antitumor activity in vitro against three cancer cell lines. Among them, the most highly active analogue 26 inhibited the growth of HeLa, and A549 cell lines with IC₅₀ values at 0.75, and 1.02 μM, respectively, indicating excellent selectivity over non-tumoural cell line HEK-293 (IC₅₀ = 29.94 μM) which suggested that the target compounds might possess a high safety index. Moreover, cell cycle analysis illustrated that the analogue 26 significantly induced HeLa cells arrest in G2/M phase, meanwhile the compound could dramatically affect cell morphology and microtubule networks. In addition, compound 28 exhibited potent anti-tubulin activity with IC₅₀ values of 9.90 μM, and molecular docking studies revealed the analogue occupied the colchicine-binding site of tubulin. These observations suggest that [1,2,4]triazolo[1,5-a]pyrimidines represent a new class of tubulin polymerization inhibitors and well worth further investigation aiming to generate potential anticancer agents.     

Development of 5-hydroxypyrazole derivatives as reversible inhibitors of lysine specific demethylase 1

A series of reversible inhibitors of lysine specific demethylase 1 (LSD1) with a 5-hydroxypyrazole scaffold have been developed from compound 7, which was identified from the patent literature. Surface plasmon resonance (SPR) and biochemical analysis showed it to be a reversible LSD1 inhibitor with an IC₅₀ value of 0.23 µM. Optimisation of this compound by rational design afforded compounds with K_d values of <10 nM. In human THP-1 cells, these compounds were found to upregulate the expression of the surrogate cellular biomarker CD86. Compound 11p was found to have moderate oral bioavailability in mice suggesting its potential for use as an in vivo tool compound.     

Identifying the novel inhibitors of lysine-specific demethylase 1 (LSD1) combining pharmacophore-based and structure-based virtual screening

Abstract

Lysine-specific demethylase 1 (LSD1) has been reported to connect with a range of solid tumors. Thus, the exploration of LSD1 inhibitors has emerged as an effective strategy for cancer treatment. In this study, we constructed a pharmacophore model based on a series of flavin adenine dinucleotide (FAD)-competing inhibitors bearing triazole???dithiocarbamate scaffold combining docking, structure–activity relationship (SAR) study, and molecular dynamic (MD) simulation. Meanwhile, another pharmacophore model was also constructed manually, relying on several speculated substrate-competing inhibitors and reported putative vital interactions with LSD1. On the basis of the two pharmacophore models, multi-step virtual screenings (VSs) were performed against substrate-binding pocket and FAD-binding pocket, respectively, combining pharmacophore-based and structure-based strategy to exploit novel LSD1 inhibitors. After bioassay evaluation, four compounds among 21 hits with diverse and novel scaffolds exhibited inhibition activity at the range of 3.63–101.43?μM. Furthermore, substructure-based enrichment was performed, and four compounds with a more potent activity were identified. After that, the time-dependent assay proved that the most potent compound with IC₅₀ 2.21?μM inhibits LSD1 activity in a manner of time-independent. In addition, the compound exhibited a cellular inhibitory effect against LSD1 in MGC-803 cells and may inhibit cell migration and invasion by reversing EMT in cultured gastric cancer cells. Considering the binding mode and SAR of the series of compounds, we could roughly deem that these compounds containing 3-methylxanthine scaffold act through occupying substrate-binding pocket competitively. This study presented a new starting point to develop novel LSD1 inhibitors.     

Design,synthesis and evaluation of γ-turn mimetics as LSD1-selective inhibitors

Lysine-specific demethylase 1 (LSD1) is an attractive molecular target for cancer therapy. We have previously reported potent LSD1-selective inhibitors (i.e., NCD18, NCD38, and their analogs) consisting of trans-2-phenylcyclopropylamine (PCPA) or trans-2-arylcyclopropylamine (ACPA) and a lysine moiety that could form a γ-turn structure in the active site of LSD1. Herein we report the design, synthesis and evaluation of γ-turn mimetic compounds for further improvement of LSD1 inhibitory activity and anticancer activity. Among a series of γ-turn mimetic compounds synthesized by a Mitsunobu-reaction-based amination strategy, we identified 1n as a potent and selective LSD1 inhibitor. Compound 1n induced cell cycle arrest and apoptosis through histone methylation in human lung cancer cells. The γ-turn mimetics approach should offer new insights into drug design for LSD1-selective inhibitors.     

Trisubstituted ureas as potent and selective mPGES-1 inhibitors

A novel series of trisubstituted ureas has been identified as potent and selective mPGES-1 inhibitors. These compounds are selective over other prostanoid enzymes such as PGF synthase and TX synthase. This series of inhibitors was developed by lead optimization of a hit from an internal HTS campaign. Lead compound 42 is potent in A549 cell assay (IC₅₀ of 0.34 μM) and in human whole blood assay (IC₅₀ of 2.1 μM). An efficient and versatile one-pot strategy for the formation of ureas, involving a reductive amination, was developed to generate these inhibitors.     

Mono-carbonyl curcumin analogues as 11β-hydroxysteroid dehydrogenase 1 inhibitors

A series of structurally novel mono-carbonyl curcumin analogues have been synthesized and biologically evaluated to test their inhibitory potencies and the structure–activity relationship (SAR) on human and rat 11β-hydroxysteroid dehydrogenase isoform (11β-HSD1) activities. 11β-HSD1 selective inhibitors have been discovered and compound A10 is discovered as a very potent with an IC₅₀ value of 97 nM without inhibiting 11β-HSD2.     

Identification of selective and reversible LSD1 inhibitors with anti-metastasis activity by high-throughput docking

The overexpression of lysine specific demethylase 1 (LSD1) has been reported in various human tumors. There is increasing interest in targeting LSD1 with small molecules for cancer treatment. A released structure of an LSD1 kinase domain in complex with FAD was used to set up a low-cost high-throughput docking protocol for quick identification of LSD1 inhibitors. The most promising hit L05 was confirmed to be a potent, selective and reversible LSD1 inhibitor and displayed marked inhibition of colorectal cells migration without significant cytotoxicity.     

Novel quinoline-3-carboxamides (Part 2): Design,optimization and synthesis of quinoline based scaffold as EGFR inhibitors with potent anticancer activity

EGFR has a key role in cell growth. Its mutation and overexpression share in epithelial malignancies and tumor growth. Quinazoline and quinoline derivatives are common anticancer intracellular inhibitors of EGFR kinase, and their optimization is an important issue for development of potent targeted anticancer agents. Based on these facts, different strategies were used for optimizing our reported quinoline-3-carboxamide compound III (EGFR IC₅₀ = 5.283 µM and MCF-7 IC₅₀ = 3.46 µM) through different molecular modeling techniques. The optimized compounds were synthesized and subjected to EGFR binding assay and accordingly some more potent inhibitors were obtained. The most potent quinoline-3-carboxamides were the furan derivative 5o; thiophene derivative 6b; and benzyloxy derivative 10 showing EGFR IC₅₀ values 2.61, 0.49 and 1.73 μM, respectively. Furthermore, the anticancer activity of compounds eliciting potent EGFR inhibition (5o, 5p, 6b, 8a, 8b, and 10) was evaluated against MCF-7 cell line where they exhibited IC₅₀ values 3.355, 3.647, 5.069, 3.617, 0.839 and 10.85 μM, respectively. Compound 6b was selected as lead structure for further optimization hoping to produce more potent EGFR inhibitors.     

Natural withanolide-based lysine-specific demethylase 1 inhibitors for antitumor metastasis activity

Lysine specific demethylase 1 (LSD1), which is overexpressed in several human cancers and acts as a demethylase of histone 3, lysine 4 and lysine 9, has become an attractive therapeutic target for cancer therapy. Based on our previous systematic studies, withanolides are important secondary metabolites mostly from the Solanaceae family of plants, which are crucial agents for cancer treatment. Here, withanolides were characterized as LSD1 inhibitors, especially withaferin A, with an IC₅₀ value of 3.04 μM. In vitro bioactivity assays and virtual molecular docking indicated that withaferin A could inhibit MDA-MB-231 cell migration by inhibiting intracellular LSD1 activity. These findings provide a new withanolide-based natural molecular skeleton for LSD1 inhibitors with potential antitumor activity.     

4-Hydroxy-3-methylbenzofuran-2-carbohydrazones as novel LSD1 inhibitors

Histone lysine specific demethylase 1 (LSD1 or KDM1A) is a potential therapeutic target in oncology due to its overexpression in various human tumors. We report herein a new class of benzofuran acylhydrazones as potent LSD1 inhibitors. Among the 31 compounds prepared, 14 compounds exhibited excellent LSD1 inhibitory activity with IC₅₀ values ranging from 7.2 to 68.8 nM. In cellular assays, several compounds inhibited the proliferations of various cancer cell lines, including PC-3, MCG-803, U87 MG, PANC-1, HT-29 and MCF-7. This opens up the opportunity for further optimization and investigation of this class compounds for potential cancer treatment.