European Journal of Medicinal Chemistry最新文献

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) regulates programmed cell death and inflammation, contributing to a wide range of human pathologies, including inflammatory disorders, neurodegenerative conditions, and cancer. Despite this, no RIPK1 positron emission tomography (PET) ligand with significant in vivo specificity has been reported to date. In this work, we designed and synthesized a new family of dihydropyrazole-cored ligands suitable for ¹⁸F-labeling at the late stage. Among these, WL8 showed a strong binding affinity to RIPK1 (EC₅₀ = 19.9 nM, K_d = 25 nM) and was successfully labeled with ¹⁸F in the 6-position of pyridine ring, yielding a high radiochemistry yield of 27.9 % (decay-corrected) and a high molar activity of 18.8–31.2 GBq/μmol. In in vitro autoradiography, [¹⁸F]WL8 showed some specific binding in the brain sections of rats and lipopolysaccharide (LPS) model mice. Preliminary PET studies in rat brains revealed that [¹⁸F]WL8 could efficiently penetrate the blood-brain barrier and was rapidly washed out. As anticipated, [¹⁸F]WL8 exhibited a high initial uptake (brain_2min = 4.80 % ID/g) in mouse brains, followed by a rapid washout (brain_60min = 0.14 % ID/g), although no clear specific binding to RIPK1 was observed. Moderate in vivo stability was noted for [¹⁸F]WL8 in mouse brains with 35.2 % of the parent fraction remaining after 30 min post-administration. Altogether, our work broadens the landscape and offers a new chemotype for RIPK1 PET ligand development.

Natural product evodiamine (Evo) and its synthetic derivatives represent an attractive dual Topo 1/2 inhibitors with broad-spectrum antitumor efficacy. However, the clinical applications of these compounds have been impeded by their poor aqueous solubility. Herein, a series of water-soluble 10-substituted-N(14)-phenylevodiamine derivatives were designed and synthesized. The most potent compound 45 featuring a quaternary ammonium salt fragment achieved robust aqueous solubility and nanomolar potency against a panel of human hepatoma cell lines Huh7, HepG2, SK-Hep-1, SMMC-7721, and SMMC-7721/DOX (doxorubicin-resistant cell). Further studies revealed that 45 could inhibit Topo 1 and Topo 2, induce apoptosis, arrest the cell cycle at the G2/M stage and inhibit the migration and invasion. Compound 45 exhibited potent antitumor activity (TGI = 51.1 %, 10 mg/kg) in the Huh7 xenograft model with acceptable safety profile. In addition, a 21-day long-term dose toxicity study confirmed that the maximum tolerated dose of compound 45 was 20 mg/kg. Overall, this study presented a promising Evo-derived candidate for the treatment of hepatocellular carcinoma.

In this work, we describe an improved series of N-phenylpyrrolamide inhibitors that exhibit potent activity against DNA gyrase and are highly effective against high-priority gram-positive bacteria. The most potent compounds show low nanomolar IC₅₀ values against Escherichia coli DNA gyrase, and in addition, compound 7c also inhibits E. coli topoisomerase IV in the nanomolar concentration range, making it a promising candidate for the development of potent dual inhibitors for these enzymes. All tested compounds show high selectivity towards the human isoform DNA topoisomerase IIα. Compounds 6a, 6d, 6e and 6f show MIC values between 0.031 and 0.0625 μg/mL against vancomycin-intermediate S. aureus (VISA) and Enterococcus faecalis strains. Compound 6g shows an inhibitory effect against the methicillin-resistant S. aureus strain (MRSA) with a MIC of 0.0625 μg/mL and against the E. faecalis strain with a MIC of 0.125 μg/mL. In a time-kill assay, compound 6d showed a dose-dependent bactericidal effect on the MRSA strain and achieved bactericidal activity at 8 × MIC after 8 h. The duration of the post-antibiotic effect (PAE) on the MRSA strain for compound 6d was 2 h, which corresponds to the PAE duration for ciprofloxacin. The compounds were not cytotoxic at effective concentrations, as determined in an MTS assay on the MCF-7 breast cancer cell line.

In this study, a series of novel thieno [3, 2-b]pyridinone derivatives were designed and synthesized using a scaffold hopping strategy. Six compounds showed potent anti-mycobacterial activity (minimum inhibitory concentration (MIC) ≤ 1 μg/mL) against Mycobacterium tuberculosis (Mtb) UAlRa. Compound 6c displayed good activity against Mtb UAlRv (MIC = 0.5–1 μg/mL). Compounds 6c and 6i also showed activity against Mtb UAlRa in macrophages and exhibited low cytotoxicity against LO-2 cells. The selected compounds displayed a narrow antibacterial spectrum, with no activity against representative Gram-positive, Gram-negative bacteria, as well as fungi. Furthermore, compound 6c demonstrated favorable oral pharmacokinetic properties with a T_1/2 value of 47.99 h and exhibited good in vivo activity in an acute mouse model of tuberculosis (TB). The target of compound 6c was identified as a NADH-dependent enoyl-acyl carrier protein reductase (InhA) by genome sequencing of spontaneously compound 6c-resistant Mtb mutants, indicating that compound 6c may not require activation and can directly target InhA. In vitro antimicrobial assays against a recombinant M. smegmatis overexpressing the Mtb-InhA, along with InhA inhibition assays, confirmed that InhA is the target of thieno [3, 2-b]pyridinone derivatives. Overall, this study identified thieno [3, 2-b]pyridinone scaffold as a novel chemotype that is promising for the development of anti-TB agents.

Currently, as the largest family of E3 ubiquitin ligases, Skp1-Cullin 1-F-box (SCF) E3 ligase complexes have attracted extensive attention. Among SCF complexes, Skp2, β-TrCP, and FBXW7 have undergone extensive research on their structures and functions. Previous studies suggest Skp2, β-TrCP, and FBXW7 are overexpressed in numerous cancers. Thus, the SCF E3 ligase complex has become a significant target for the development of anti-cancer drugs. Over the past few decades, a variety of anti-tumor inhibitors targeting the SCF E3 ligase complex have been attempted. However, since almost none of the SCF E3 ligase inhibitors passed clinical trials, the design and synthesis of the new inhibitors are needed. Here, we will introduce the structure and function of Skp2, β-TrCP, and FBXW7, their connections with cancer development, the relevant in vitro and in vivo activities, selectivity, structure-activity relationships, and the therapeutic or preventive application of small molecule inhibitors targeting these three F-box proteins reported in the patent (2010–present). This information will help develop drugs targeting the SCF E3 ubiquitin ligase, providing new strategies for future cancer treatments.

Alzheimer's disease (AD, also known as dementia) has become a serious global health problem along with population aging, and neuroinflammation is the underlying cause of cognitive impairment in the brain. Nowadays, the development of multitarget anti-AD drugs is considered to be one effective approach. Imidazolylacetophenone oxime ethers or esters (IOEs) were multifunctional agents with neuroinflammation inhibition, metal chelation, antioxidant and neuroprotection properties against Alzheimer's disease. In this study, IOEs derivatives 1−8 were obtained by structural modifications of the oxime and imidazole groups, and the SARs showed that (Z)-oxime ether (derivative 2) had stronger anti-neuroinflammatory and neuroprotective ability than (E)-congener. Then, IOEs derivatives 9−30 were synthesized based on target-directed ligands and activity-based groups hybridization strategy. In vitro anti-AD activity screening revealed that some derivatives exhibited potentially multifunctional effects, among which derivative 28 exhibited the strongest inhibitory activity on NO production with EC₅₀ value of 0.49 μM, and had neuroprotective effects on 6-OHDA-induced cell damage and RSL3-induced ferroptosis. The anti-neuroinflammatory mechanism showed that 28 could inhibit the release of pro-inflammatory factors PGE₂ and TNF-α, down-regulate the expression of iNOS and COX-2 proteins, and promote the polarization of BV-2 cells from pro-inflammatory M1 phenotype to anti-inflammatory M2 phenotype. In addition, 28 can dose-dependently inhibit acetylcholinesterase (AChE) and Aβ₄₂ aggregation. Moreover, the selected nuclide [¹⁸F]-labeled 28 was synthesized to explore its biodistribution by micro-PET/CT, of which 28 can penetrate the blood-brain barrier (BBB). These results shed light on the potential of 28 as a new multifunctional candidate for AD treatment.

Tumor proliferation and metastasis are intricately linked to blood vessel formation, with vascular endothelial growth factor (VEGF) playing a pivotal role in orchestrating angiogenesis throughout tumor progression. Pseudolaric acid B (PAB) has emerged as a potent inhibitor of tumor cell proliferation, migration, and angiogenesis. In efforts to enhance its efficacy, 37 derivatives of PAB were synthesized and assessed for their capacity to suppress VEGF secretion in SiHa cells under hypoxic conditions. Notably, majority of these derivatives exhibited significant inhibition of VEGF protein secretion without inducing cytotoxicity. Among them, compound M2 displayed the most potent inhibitory activity, with an IC₅₀ value of 0.68 μM, outperforming the lead compound PAB (IC₅₀ = 5.44 μM). Compound M2 not only curbed the migration and angiogenesis of HUVECs under hypoxic conditions but also hindered the invasion of SiHa cells. Mechanistic investigations unveiled that compound M2 may impede the accumulation and nuclear translocation of hypoxia-inducible factor 1α (HIF-1α) in SiHa cells, thereby downregulating VEGF expression. This inhibitory effect on HIF-1α was corroborated by experiments utilizing the protease inhibitor MG-132 and protein synthesis inhibitor CHX, indicating that compound M2 diminishes HIF-1α levels by reducing its synthesis. Furthermore, compound M2 was observed to modulate the PI3K/AKT/mTOR and MAPK signaling pathways in tumor cells, thereby regulating HIF-1α translation and synthesis. In vivo studies demonstrated that compound M2 exhibited low toxicity and effectively curbed tumor growth. Immunohistochemistry analyses validated that compound M2 effectively suppressed the expression of HIF-1α and VEGF in tumor tissues, underscoring its potential as a promising therapeutic agent for targeting tumor angiogenesis.

Leucine-rich repeat kinase 2 (LRRK2) has been reported to be associated with familial and idiopathic Parkinson's disease (PD) risk and is a promising target for drug discovery against PD. To identify novel and effective LRRK2 inhibitors, an ensemble virtual screening strategy by combining fingerprint similarity, complex-based pharmacophore and structure-based molecular docking was proposed and applied. Using this strategy, we finally selected 25 compounds from ∼1.7 million compounds for in vitro and in vivo tests. Firstly, the kinase inhibitory activity tests of compounds based on ADP-Glo assay identified three most potent compounds LY2023-19, LY2023-24 and LY2023-25 with IC₅₀ of 556.4 nM, 218.1 nM and 22.4 nM for LRRK2 G2019S mutant, respectively. The further cellular experiments also indicated that three hit compounds significantly inhibited Ser935 phosphorylation of both wide-type and G2019S LRRK2 with IC₅₀ ranging from 27 nM to 1674 nM in HEK293T cells. The MD simulations of three compounds and G2019S LRRK2 showed the hydrogen bond formed by Glu1948 and Ala1950 is crucial for the binding of LRRK2. Afterwards, 6-OHDA-induced PD zebrafish model was constructed to evaluate the neuroprotective effects of hit compounds. The locomotion of the 6-OHDA treated zebrafish larvae was improved after treatment with LY2023-24. The obtained results can provide valuable guidance for the development of PD drugs by targeting LRRK2.

Chikungunya virus (CHIKV) is responsible for the most endemic alphavirus infections called Chikungunya. The endemicity of Chikungunya has increased over the past two decades, and it is a pathogen with pandemic potential. There is currently no approved direct-acting antiviral to treat the disease. As part of our antiviral drug discovery program focused on alphaviruses and the non-structural protein 2 protease, we discovered that J12 and J13 can inhibit CHIKV nsP2 protease and block the replication of CHIKV in cell cultures. Both compounds are metabolically stable to human liver microsomal and S9 enzymes. J13 has excellent oral bioavailability in pharmacokinetics studies in mice and ameliorated Chikungunya symptoms in preliminary efficacy studies in mice. J13 exhibited an excellent safety profile in in vitro safety pharmacology and off-target screening assays, making J13 and its analogs good candidates for drug development against Chikungunya.

Pyridazinone derivatives have been extensively used as anticancer agents. IMB5036 is a structure specific pyridazinone compound with potential antitumor activity via targeting KSRP protein which controls gene expression at multiple levels. In this study, fifteen IMB5036 analogues were synthesized and preliminary structure-activity relationships were explored. Among them, compounds 8 and 10 exhibited remarkably anti-proliferation of various cancer cells and a good cancer cell selectivity (against human fetal hepatocyte L02 cells). More detailed investigation was included that both 8 and 10 inhibited colony formation and migration in concentration-dependent mode against MCF-7 cells. Additionally, 8 and 10 induced apoptosis and cell cycle arrest, decreased mitochondrial membrane potential, damaged DNA, and increased reactive oxygen species. Moreover, 8 displayed a potent antitumor efficacy (TGI = 74.2 %, at a dose of 30 mg/kg) in MCF-7 xenograft model by i.p. injection. Further, we synthesized a biotinylated probe 16 for identifying the detail domain of KSRP. Through pull down assay and molecular docking study, we validated that the KH23 domain functioned as the binding pocket for the compounds. Thus, compound 8 was identified as a novel targeting KSRP pyridazinone-based compound and exhibited excellent antitumor activity both in vitro and in vivo.