[1,2,3]Triazolo[4,5-d]pyrimidine derivatives incorporating (thio)urea moiety as a novel scaffold for LSD1 inhibitors

Structural modification strategies of triazoles in anticancer drug development

The triazole functional group plays a pivotal role in the composition of biomolecules with potent anticancer activities, including numerous clinically approved drugs. The strategic utilization of the triazole fragment in the rational modification of lead compounds has demonstrated its ability to improve anticancer activities, enhance selectivity, optimize pharmacokinetic properties, and overcome resistance. There has been significant interest in triazole-containing hybrids in recent years due to their remarkable anticancer potential. However, previous reviews on triazoles in cancer treatment have failed to provide tailored design strategies specific to these compounds. Herein, we present an overview of design strategies encompassing a structure-modification approach for incorporating triazoles into hybrid molecules. This review offers valuable references and briefly introduces the synthesis of triazole derivatives, thereby paving the way for further research and advancements in the field of effective and targeted anticancer therapies.

Lysine-Specific Demethylase 1 Inhibitors: A Comprehensive Review Utilizing Computer-Aided Drug Design Technologies

Lysine-specific demethylase 1 (LSD1/KDM1A) has emerged as a promising therapeutic target for treating various cancers (such as breast cancer, liver cancer, etc.) and other diseases (blood diseases, cardiovascular diseases, etc.), owing to its observed overexpression, thereby presenting significant opportunities in drug development. Since its discovery in 2004, extensive research has been conducted on LSD1 inhibitors, with notable contributions from computational approaches. This review systematically summarizes LSD1 inhibitors investigated through computer-aided drug design (CADD) technologies since 2010, showcasing a diverse range of chemical scaffolds, including phenelzine derivatives, tranylcypromine (abbreviated as TCP or 2-PCPA) derivatives, nitrogen-containing heterocyclic (pyridine, pyrimidine, azole, thieno[3,2-b]pyrrole, indole, quinoline and benzoxazole) derivatives, natural products (including sanguinarine, phenolic compounds and resveratrol derivatives, flavonoids and other natural products) and others (including thiourea compounds, Fenoldopam and Raloxifene, (4-cyanophenyl)glycine derivatives, propargylamine and benzohydrazide derivatives and inhibitors discovered through AI techniques). Computational techniques, such as virtual screening, molecular docking and 3D-QSAR models, have played a pivotal role in elucidating the interactions between these inhibitors and LSD1. Moreover, the integration of cutting-edge technologies such as artificial intelligence holds promise in facilitating the discovery of novel LSD1 inhibitors. The comprehensive insights presented in this review aim to provide valuable information for advancing further research on LSD1 inhibitors.

A Quinquennial Review of Potent LSD1 Inhibitors Explored for the Treatment of Different Cancers, with Special Focus on SAR Studies

Cancer bears a significant share of global mortality. The enzyme Lysine Specific Demethylase 1 (LSD1, also known as KDM1A), since its discovery in 2004, has captured the attention of cancer researchers due to its overexpression in several cancers like acute myeloid leukaemia (AML), solid tumours, etc. The Lysine Specific Demethylase (LSD1) downregulation is reported to have an effect on cancer proliferation, migration, and invasion. Therefore, research to discover safer and more potent LSD1 inhibitors can pave the way for the development of better cancer therapeutics. These efforts have resulted in the synthesis of many types of derivatives containing diverse structural nuclei. The present manuscript describes the role of Lysine Specific Demethylase 1 (LSD1) in carcinogenesis, reviews the LSD1 inhibitors explored in the past five years and discusses their comprehensive structural activity characteristics apart from the thorough description of LSD1. Besides, the potential challenges, opportunities, and future perspectives in the development of LSD1 inhibitors are also discussed. The review suggests that tranylcypromine derivatives are the most promising potent LSD1 inhibitors, followed by triazole and pyrimidine derivatives with IC₅₀ values in the nanomolar and sub-micromolar range. A number of potent LSD1 inhibitors derived from natural sources like resveratrol, protoberberine alkaloids, curcumin, etc. are also discussed. The structural-activity relationships discussed in the manuscript can be exploited to design potent and relatively safer LSD1 inhibitors as anticancer agents.

Triazole-fused pyrimidines in target-based anticancer drug discovery

In recent decades, the development of targeted drugs has featured prominently in the treatment of cancer, which is among the major causes of mortality globally. Triazole-fused pyrimidines, a widely-used class of heterocycles in medicinal chemistry, have attracted considerable interest as potential anticancer agents that target various cancer-associated targets in recent years, demonstrating them as valuable templates for discovering novel anticancer candidates. The current review concentrates on the latest advancements of triazole-pyrimidines as target-based anticancer agents, including works published between 2007 and the present (2007-2022). The structure-activity relationships (SARs) and multiple pathways are also reviewed to shed light on the development of more effective and biotargeted anticancer candidates.

Design, synthesis and in vitro/in vivo anticancer activity of tranylcypromine-based triazolopyrimidine analogs as novel LSD1 inhibitors

Histone lysine specific demethylase 1 (LSD1) is responsible for the demethylation of mono-/dimethylated lysine residue on histone proteins. LSD1 plays an extensive and essential role in the pathogenesis and progression of many human diseases such as cancers, and thus is becoming an attractive therapeutic target for cancer treatment. Tranylcypromine (TCP) is an important chemical template for developing irreversible LSD1 inhibitors, representing a major chemotype of clinical candidates. Here we report a novel pool of TCP derivatives with triazolopyrimidine as a privileged heterocylic motif. Starting from ticagrelor, a clinically available antiplatelet agent, as a hit compound, our medicinal efforts have led to the identification of compound 9j with nanomolar inhibitory potency against LSD1 as well as broad-spectrum antiproliferative activities against tumor cells. Enzyme studies show that compound 9j is selective over MAO-A/B enzymes, and also cellular active to elevate the expression of H3K4me2 by inhibiting LSD1 in cells. Furthermore, in a H1650 xenograft mouse model, oral administration of compound 9j at low 10 and 20 mg/kg dosages could enable a significant reduction in tumor size and a remarkable extension of survival. The current work is expected to provide an additional strategy to achieve new TCP-based LSD1 inhibitors.

Learning with uncertainty to accelerate the discovery of histone lysine-specific demethylase 1A (KDM1A/LSD1) inhibitors

Machine learning including modern deep learning models has been extensively used in drug design and screening. However, reliable prediction of molecular properties is still challenging when exploring out-of-domain regimes, even for deep neural networks. Therefore, it is important to understand the uncertainty of model predictions, especially when the predictions are used to guide further experiments. In this study, we explored the utility and effectiveness of evidential uncertainty in compound screening. The evidential Graphormer model was proposed for uncertainty-guided discovery of KDM1A/LSD1 inhibitors. The benchmarking results illustrated that (i) Graphormer exhibited comparative predictive power to state-of-the-art models, and (ii) evidential regression enabled well-ranked uncertainty estimates and calibrated predictions. Subsequently, we leveraged time-splitting on the curated KDM1A/LSD1 dataset to simulate out-of-distribution predictions. The retrospective virtual screening showed that the evidential uncertainties helped reduce false positives among the top-acquired compounds and thus enabled higher experimental validation rates. The trained model was then used to virtually screen an independent in-house compound set. The top 50 compounds ranked by two different ranking strategies were experimentally validated, respectively. In general, our study highlighted the importance to understand the uncertainty in prediction, which can be recognized as an interpretable dimension to model predictions.

Epigenetic compounds targeting pharmacological target lysine specific demethylase 1 and its impact on immunotherapy, chemotherapy and radiotherapy for treatment of tumor recurrence and resistance

It has been proven that metastatic recurrence and therapeutic resistance are linked. Due to the variability of individuals and tumors, as well as the tumor's versatility in avoiding therapies, therapy resistance is more difficult to treat. Therapy resistance has significantly restricted the clinical feasibility and efficacy of tumor therapy, despite the discovery of novel compounds and therapy combinations with increasing efficacy. In several tumors, lysine specific demethylase 1 (LSD1) has been associated to metastatic recurrence and therapeutic resistance. For researchers to better comprehend how LSD1-mediated tumor therapy resistance occurs and how to overcome it in various tumors, this study focused on the role of LSD1 in tumor recurrence and therapeutic resistance. The importance of therapeutically targeted LSD1 was also discussed. Most gene pathway signatures are related to LSD1 inhibitor sensitivity. However, some gene pathway signatures, especially in AML, negatively correlate with LSD1 inhibitor sensitivity, but targeting LSD1 makes the therapy-resistant tumor sensitive to physiological doses of conventional therapy. We propose that combining LSD1 inhibitor with traditional tumor therapy can help patients attain a complete response and prevent cancer relapse.

Identification of novel indole derivatives as highly potent and efficacious LSD1 inhibitors

Lysine-specific demethylase 1 (LSD1) is a FAD-dependent histone demethylase to catalyze the demethylation of H3K4 and H3K9 and thus is an attractive target for therapeutic cancer. Starting with a high micromolar compound 17i, structure-based optimization of novel indole derivatives is described by a bioelectronic isosteric strategy. Grounded by molecular modeling, medicinal chemistry has efficiently yielded low nanomolar LSD1 inhibitors. One of the compounds, B35, exhibited excellent LSD1 inhibition (IC50 = 0.050 ± 0.005 μM) and anti-proliferation against A549 cells (IC50 = 0.74 ± 0.14 μM). The further PK studies indicated compound B35 possessed favorable metabolic stability, in which the plasma t1/2 of p.o. and i.v. were 6.27 ± 0.72 h and 8.78 ± 1.31 h, respectively. Additionally, inhibitor B35 shows a strong antitumor effect and good safety in vivo. Meanwhile, compound B35 regulated genes are closely associated with transcriptional dislocation in cancer and PI3K/AKT pathway involving IGFBP3. Taken together, B35 could be a potent LSD1 inhibitor for further drug development.

LSD1 inhibitors for anticancer therapy: a patent review (2017-present)

INTRODUCTION

Lysine-specific demethylase 1 (LSD1), which belongs to the demethylase of non-histone proteins, is believed to promote cancer cell proliferation and metastasis by modifying histones. LSD1 dysfunction may play a key role in a variety of cancers, such as acute myeloid leukemia and non-small cell lung cancer, indicating that LSD1 is a promising epigenetic target for cancer therapy. Many different types of small molecule LSD1 inhibitors have been developed and shown to inhibit tumor cell proliferation, invasion, and migration, providing a new treatment strategy for solid tumors.

AREAS COVERED

This review summarizes the progress of LSD1 inhibitor research in the last four years, including selected new patents and article publications, as well as the therapeutic potential of these compounds.

EXPERT OPINION

Natural products offer a promising prospect for developing novel potent LSD1 inhibitors, as structural design and activity of irreversible and reversible inhibitors have been continuously optimized since the discovery of the LSD1 target in 2004. The use of "microtubule-binding agents" and "dual-agent combination" has recently become a new anticancer technique, reducing the resistance and adverse reactions of traditional drugs. Several microtubule-binding drugs have been used successfully in clinical practice, providing structural scaffolds and new ideas for the development of safer drugs.

Azole-pyrimidine Hybrid Anticancer Agents: A Review of Molecular Structure, Structure Activity Relationship and Molecular Docking

Cancer has emerged as one of the leading causes of deaths globally partly due to the steady rise in anticancer drug resistance. Pyrimidine and pyrimidine-fused heterocycles are some of the privileged scaffolds in medicine, as they possess diverse biological properties. Pyrimidines containing azole nucleus possesses inestimable anticancer potency and has enormous potential to conduct the regulation of cellular pathways for selective anticancer activity. The present review outlines the molecular structure of pyrimidine-fused azoles with significant anticancer activity. The structure activity relationship and molecular docking studies have also been discussed. The current review is the first complete compilation of significant literature on the proposed topic from 2016 to 2020. The information contained in this review offers a useful insight to chemists in the design of new and potent anticancer azole-pyrimidine analogues.

Discovery of quinazoline derivatives as a novel class of potent and in vivo efficacious LSD1 inhibitors by drug repurposing

Histone lysine-specific demethylase 1 (LSD1) is an important epigenetic modulator, and is implicated in malignant transformation and tumor pathogenesis in different ways. Therefore, the inhibition of LSD1 provides an attractive therapeutic target for cancer therapy. Based on drug repurposing strategy, we screened our in-house chemical library toward LSD1, and found that the EGFR inhibitor erlotinib, an FDA-approved drug for lung cancer, possessed low potency against LSD1 (IC₅₀ = 35.80 μM). Herein, we report our further medicinal chemistry effort to obtain a highly water-soluble erlotinib analog 5k (>100 mg/mL) with significantly enhanced inhibitory activity against LSD1 (IC₅₀ = 0.69 μM) as well as higher specificity. In MGC-803 cells, 5k suppressed the demethylation of LSD1, indicating its cellular activity against the enzyme. In addition, 5k had a remarkable capacity to inhibit colony formation, suppress migration and induce apoptosis of MGC803 cells. Furthermore, in MGC-803 xenograft mouse model, 5k treatment resulted in significant reduction in tumor size by 81.6% and 96.1% at dosages of 40 and 80 mg/kg/d, respectively. Our findings indicate that erlotinib-based analogs provide a novel structural set of LSD1 inhibitors with potential for further investigation, and may serve as novel candidates for the treatment of LSD1-overexpressing cancers.

Design, synthesis and biological evaluation of novel benzofuran derivatives as potent LSD1 inhibitors

Lysine-specific demethylase 1 (LSD1) is a FAD-dependent enzyme, which has been proposed as a promising target for therapeutic cancer. Herein, a series of benzofuran derivatives were designed, synthesized and biochemical evaluated as novel LSD1 inhibitors based on scaffold hopping and conformational restriction strategy. Most of the compounds potently suppressed the enzymatic activities of LSD1 and potently inhibited tumor cells proliferation. In particular, the representative compound 17i exhibited excellent LSD1 inhibition at the molecular levels with IC₅₀ = 0.065 μM, as well as anti-proliferation against MCF-7, MGC-803, H460, A549 and THP-1 tumor cells with IC₅₀ values of 2.90 ± 0.32, 5.85 ± 0.35, 2.06 ± 0.27, 5.74 ± 1.03 and 6.15 ± 0.49 μM, respectively. The binding modes of these compounds were rationalized by molecular docking. Meanwhile, a preliminary druggability evaluation showed that compound 17i displayed favorable liver microsomal stability and weak inhibitory activity against CYPs at 10 μM. Remarkably, H460 xenograft tumors studies revealed that 17i demonstrated robust in vivo antitumor efficacy without significant side effects. All the results demonstrated that compound 17i could represent a promising lead for further development.

Reversible Lysine Specific Demethylase 1 (LSD1) Inhibitors: A Promising Wrench to Impair LSD1

As a flavin adenine dinucleotide (FAD)-dependent monoamine oxidase, lysine specific demethylase 1 (LSD1/KDM1A) functions as a transcription coactivator or corepressor to regulate the methylation of histone 3 lysine 4 and 9 (H3K4/9), and it has emerged as a promising epigenetic target for anticancer treatment. To date, numerous inhibitors targeting LSD1 have been developed, some of which are undergoing clinical trials for cancer therapy. Although only two reversible LSD1 inhibitors CC-90011 and SP-2577 are in the clinical stage, the past decade has seen remarkable advances in the development of reversible LSD1 inhibitors. Herein, we provide a comprehensive review about structures, biological evaluation, and structure-activity relationship (SAR) of reversible LSD1 inhibitors.

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.

Two new sesquiterpenes from the rhizomes of Atractylodes macrocephala and their biological activities

Two new sesquiterpenes, named selina-4(14),7,11-trien-9-ol (1) and selina-4(14),11-dien-7-ol (2), along with two known compounds were isolated from rhizomes of Atractylodes macrocephala Koidz. All structures were assigned on the basis of detailed spectroscopic analyses. The absolute configuration of 1 was established by TDDFT-ECD calculations. Compound 1 was found to moderately inhibit LSD1 activity with IC₅₀ value of 34.0 μM. Compounds 1 and 4 exhibited a regulate effect on Keap1-Nrf2-ARE pathway.

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.