Synthesis and biological evaluation of 4-(2-fluorophenoxy)-3,3′-bipyridine derivatives as potential c-met inhibitors

Design, bioactivity and mechanism of N'-phenyl pyridylcarbohydrazides with broad-spectrum antifungal activity

Succinate dehydrogenase inhibitors (SDHIs) as one of the fastest-growing fungicide categories for plant protection. In this study, a series of N'-phenyl pyridylcarbohydrazides as analogues of commercial SDHIs were designed and evaluated for inhibition activity on phytopathogenic fungi to search for potential novel SDHIs. The determination of antifungal activity in vitro and in vivo led to the discovery of a series of compounds with high activity and broad-spectrum property. Especially, N'-(4-fluorophenyl)picolinohydrazide (1c) and N'-(3,4-fluorophenyl)picolinohydrazide (1ae) showed 0.041-1.851 μg/mL of EC50 values on twelve fungi, superior to positive controls carbendazim and boscalid. In vivo activity, 1c at 50 μg/mL showed 61% of control efficacy at the post-treatment 9th day for the infection of P. piricola on apples, slightly smaller than 70% of carbendazim. In terms of action mechanism, 1c showed strong inhibition activity with IC50 of 0.107 μg/mL on SDH in Alternaria brassicae, superior to positive SDHI boscalid (IC50 0.182 μg/mL). Molecular docking indicated that 1c can well bind with the ubiquinone-binding region of SDH mainly by hydrogen bond, carbon hydrogen bond, π-alkyl, amide-π stacking, F-N and F-H interactions. Furthermore, scanning and transmission electron micrographs showed that 1c was able to obviously change the structure of mycelia and cell membrane. Fluorescence staining analysis showed that 1c could increase both the intracellular reactive oxygen species level and mitochondrial membrane potential. Finally, seed germination test, seedling growth test and cytotoxicity assay showed that 1c had very low toxicity to plant growth and mammalian cells. Thus, N'-phenyl pyridylcarbohydrazides especially 1c and 1ae can be considered promising fungicide alternatives for plant protection.

Effect of 6,6-Substitution on 2,2'-Bipyridine and Probing Biomolecular Interaction Through Experimental and Computational Studies Towards Anticancer Potency

The current study focuses on the cytotoxicity assessment of 6,6'-substituted 2,2'-bipyridine derivatives containing functional groups, namely methyl (-CH3, L1), acid (-COOH, L2), ester (-COOCH3, L3), semicarbozone (-CONHNH2, L4). The ligands exhibited high solubility in dimethyl sulfoxide (DMSO) and moderately soluble in dimethyl formamide (DMF), acetonitrile (ACN) and low solubility in water. The ligands display a significant π→π* transition in the region of 270 nm to 305 nm. The emission spectra of the ligands reveal a prominent band in the 300 nm to 450 nm range, with a Stokes shift of 120 cm- 1. UV-VIS spectra analysis, the ligands (L1-L4, 1mM) demonstrated stability in various environmental like water, glutathione (GSH, 1mM), and MTT condition (10% DMSO). The interaction of ligands with DNA was assessed through calf thymus deoxyribonucleic acid (ctDNA) binding assay, viscosity studies, and ethidium bromide (EtBr) displacement assay, with L1 and L4 exhibiting the highest interaction. The MTT assay was conducted for 24 h and 48 h using ligands (L1-L4) and doxorubicin in MCF-7, HeLa, and L929 cell lines. Ligand L4 showed high potency IC50 values after 48 h in MCF-7 (1.28 µM) and HeLa (1.81 µM), but its potency is lower than doxorubicin. Overall, for the first time these results suggest that L4 has high anticancer activity at lower concentrations against breast and cervical cancers.

Structure-Activity Relationship Studies of Substituted 2-Phenyl-1,2,4-triazine-3,5(2H,4H)-dione Analogues: Development of Potent eEF2K Degraders against Triple-Negative Breast Cancer

eEF2K, an atypical alpha-kinase, is responsible for regulating protein synthesis and energy homeostasis. Aberrant eEF2K function has been linked to various human cancers, including triple-negative breast cancer (TNBC). However, limited cellular activity of current eEF2K modulators impedes their clinical application. Based on the 2-phenyl-1,2,4-triazine-3,5(2H,4H)-dione scaffold of our hits I4 and C1, structure-activity relationship analysis led to the discovery of several more active derivatives (e.g., 19, 34, and 36) in inhibiting the viability of TNBC cell line MDA-MB-231. Moreover, the most potent compound 36 significantly suppresses the viability, proliferation, and migration of both MDA-MB-231 and HCC1806 cell lines. Mechanistically, compound 36 has a high binding affinity for the eEF2K protein and effectively induces its degradation. Additionally, 36 exerts a comparable tumor-suppressive effect to paclitaxel in an MDA-MB-231 cell xenograft mouse model with no obvious toxicity, demonstrating that compound 36 could be developed as a potential novel therapeutic for TNBC treatment.

Research Progresses of Targeted Therapy and Immunotherapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, with nearly one million new cases and deaths every year. Owing to the complex pathogenesis, hidden early symptoms, rapidly developing processes, and poor prognosis, the morbidity and mortality of HCC are increasing yearly. With the progress being made in modern medicine, the treatment of HCC is no longer limited to traditional methods. Targeted therapy and immunotherapy have emerged to treat advanced and metastatic HCC in recent years. Since Sorafenib is the first molecular targeting drug against angiogenesis, targeted drugs for HCC are continually emerging. Moreover, immunotherapy plays a vital role in clinical trials. In particular, the application of immune checkpoint inhibitors, which have received increasing attention in the field of cancer treatment, is a possible research path. Interestingly, these two therapies generally complement each other at some stages of HCC, bringing new hope for patients with advanced HCC. In this paper, we discuss the research progress of targeted therapy and immunotherapy for HCC in recent years, which will provide a reference for the further development of drugs for HCC.

Synthesis of antimicrobial azoloazines and molecular docking for inhibiting COVID-19

Diverse new azoloazines were synthesized from the reaction of fluorinated hydrazonoyl chlorides with heterocyclic thiones, 1,8-diaminonaphthalene, ketene aminal derivatives, and 4-amino-5-triflouromethyl-1,2,4-triazole-2-thiol. The mechanistic pathways and the structures of all synthesized derivatives were discussed and assured based on the available spectral data. The synthesized azoloazine derivatives were evaluated for their antifungal and antibacterial activities through zone of inhibition measurement. The results revealed promising antifungal activities for compounds 4, 5, 17a,b, 19, and 25 against the pathogenic fungal strains used; Aspergillus flavus and Candida albicans compared to ketoconazole. In addition, compounds 4, 5, 19, and 25 showed moderate antibacterial activities against most tested bacterial strains. Molecular docking studies of the promising compounds were carried out on leucyl-tRNA synthetase active site of Candida albicans, suggesting good binding in the active site forming stable complexes. Moreover, docking of the synthesized compounds was performed on the active site of SARS-CoV-2 3CLpro to predict their potential as a hopeful anti-COVID and to investigate their binding pattern.

Design, synthesis and biological evaluation of novel N-sulfonylamidine-based derivatives as c-Met inhibitors via Cu-catalyzed three-component reaction

In our continuing efforts to develop novel c-Met inhibitors as potential anticancer candidates, a series of new N-sulfonylamidine derivatives were designed, synthesized via Cu-catalyzed multicomponent reaction (MCR) as the key step, and evaluated for their in vitro biological activities against c-Met kinase and four cancer cell lines (A549, HT-29, MKN-45 and MDA-MB-231). Most of the target compounds showed moderate to significant potency at both the enzyme-based and cell-based assay and possessed selectivity for A549 and HT-29 cancer cell lines. The preliminary SAR studies demonstrated that compound 26af (c-Met IC₅₀ = 2.89 nM) was the most promising compound compared with the positive foretinib, which exhibited the remarkable antiproliferative activities, with IC₅₀ values ranging from 0.28 to 0.72 μM. Mechanistic studies of 26af showed the anticancer activity was closely related to the blocking phosphorylation of c-Met, leading to cell cycle arresting at G2/M phase and apoptosis of A549 cells by a concentration-dependent manner. The promising compound 26af was further identified as a relatively selective inhibitor of c-Met kinase, which also possessed an acceptable safety profile and favorable pharmacokinetic properties in BALB/c mouse. The favorable drug-likeness of 26af suggested that N-sulfonylamidines may be used as a promising scaffold for antitumor drug development. Additionally, the docking study and molecular dynamics simulations of 26af revealed a common mode of interaction with the binding site of c-Met. These positive results indicated that compound 26af is a potential anti-cancer candidate for clinical trials, and deserves further development as a selective c-Met inhibitor.

Design, synthesis and biological evaluation of novel N-[4-(2-fluorophenoxy)pyridin-2-yl]cyclopropanecarboxamide derivatives as potential c-Met kinase inhibitors

Three series of novel 4-phenoxypyridine derivatives containing 4-methyl-6-oxo-1,6-dihydropyridazine- 3-carboxamide, 5-methyl-4-oxo-1,4-dihydropyridazine-3-carboxamide and 4-methyl-3,5-dioxo-2,3,4,5- tetrahydro-1,2,4-triazine-6-carboxamide moieties were synthesized and evaluated for their in vitro inhibitory activitives against c-Met kinase and cytotoxic activitives against A549, H460, HT-29 cancer cell lines. The results indicated that most of the compounds showed moderate to good antitumor activitives. The most promising compound 26a (with c-Met IC₅₀ value of 0.016 μM) showed remarkable cytotoxicity against A549, H460, and HT-29 cell lines with IC₅₀ values of 1.59 μM, 0.72 μM and 0.56 μM, respectively. Their preliminary structure-activity relationships (SARs) studies indicate that 4-methyl-3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine-6-carboxamide was more preferred as linker part, and electron-withdrawing groups on the terminal phenyl rings are beneficial for improving the antitumor activitives. Furthermore, the colony formation, acridine orange/ethidium bromide (AO/EB) staining, apoptosis, and wound-healing assay of 26a were performed on HT-29 and/or A549 cell lines.

Synthesis of 3-hetarylpyrroles by Suzuki–Miyaura cross-coupling

1-[tert-Butyl(diphenyl)silyl]pyrrol-3-ylboronic acid was obtained from pyrrole in three steps. Its Suzuki–Miyaura cross-coupling with functionalized pyridinyl and pyrimidinyl bromides afforded new promising 3-hetaryl-1H-pyrroles.