Synthesis and biological evaluation of novel 6,11-dihydro-5 H -benzo[e]pyrimido- [5,4- b ][1,4]diazepine derivatives as potential c-Met inhibitors

Design, Synthesis, and Biological Evaluation of 2-Substituted Aniline Pyrimidine Derivatives as Potent Dual Mer/c-Met Inhibitors

Mer and c-Met kinases, which are commonly overexpressed in various tumors, are ideal targets for the development of antitumor drugs. This study focuses on the design, synthesis, and evaluation of several 2-substituted aniline pyrimidine derivatives as highly potent dual inhibitors of Mer and c-Met kinases for effective tumor treatment. Compound 18c emerged as a standout candidate, demonstrating robust inhibitory activity against Mer and c-Met kinases, with IC50 values of 18.5 ± 2.3 nM and 33.6 ± 4.3 nM, respectively. Additionally, compound 18c displayed good antiproliferative activities on HepG2, MDA-MB-231, and HCT116 cancer cells, along with favorable safety profiles in hERG testing. Notably, it exhibited exceptional liver microsomal stability in vitro, with a half-life of 53.1 min in human liver microsome. Compound 18c also exhibited dose-dependent cytotoxicity and hindered migration of HCT116 cancer cells, as demonstrated in apoptosis and migration assays. These findings collectively suggest that compound 18c holds promise as a dual Mer/c-Met agent for cancer treatment.

Recent progress on vascular endothelial growth factor receptor inhibitors with dual targeting capabilities for tumor therapy

Vascular endothelial growth factor receptors (VEGFRs) are a family of receptor protein tyrosine kinases that play an important role in the regulation of tumor-induced angiogenesis. Currently, VEGFR inhibitors have been widely used in the treatment of various tumors. However, current VEGFR inhibitors are limited to a certain extent due to limited clinical efficacy and potential toxicity, which hinder their clinical application. Thus, the development of new strategies to improve the clinical outcomes and minimize the toxic effects of VEGFR inhibitors is required. Given the synergistic effect of VEGFR and other therapies in tumor development and progression, VEGFR dual-target inhibitors are becoming an attractive approach due to their favorable pharmacodynamics, low toxicity, and anti-resistant effects. This perspective provides an overview of the development of VEGFR dual-target inhibitors from multiple aspects, including rational target combinations, drug discovery strategies, structure–activity relationships and future directions.

Anticancer activity of pyrimidodiazepines based on 2-chloro-4-anilinoquinazoline: synthesis, DNA binding and molecular docking

Multidrug resistance to chemotherapy is a critical health problem associated with mutation of the therapeutic target. Therefore, the development of anticancer agents remains a challenge to overcome cancer cell resistance. Herein, a new series of quinazoline-based pyrimidodiazepines 16a-g were synthesized by the cyclocondensation reaction of 2-chloro-4-anilinoquinazoline-chalcones 14a-g with 2,4,5,6-tetraaminopyrimidine. All quinazoline derivatives 14a-g and 16a-g were selected by the U.S. National Cancer Institute (NCI) for testing their anticancer activity against 60 cancer cell lines of different panels of human tumors. Among the tested compounds, quinazoline-chalcone 14g displayed high antiproliferative activity with GI₅₀ values between 0.622-1.81 μM against K-562 (leukemia), RPMI-8226 (leukemia), HCT-116 (colon cancer) LOX IMVI (melanoma), and MCF7 (breast cancer) cancer cell lines. Additionally, the pyrimidodiazepines 16a and 16c exhibited high cytostatic (TGI) and cytotoxic activity (LC₅₀), where 16c showed high cytotoxic activity, which was 10.0-fold higher than the standard anticancer agent adriamycin/doxorubicin against ten cancer cell lines. COMPARE analysis revealed that 16c may possess a mechanism of action through DNA binding that is similar to that of CCNU (lomustine). DNA binding studies indicated that 14g and 16c interact with the calf thymus DNA by intercalation and groove binding, respectively. Compounds 14g, 16c and 16a displayed strong binding affinities to DNA, EGFR and VEGFR-2 receptors. None of the active compounds showed cytotoxicity against human red blood cells.

Structure-guided design and development of novel N-phenylpyrimidin-2-amine derivatives as potential c-Met inhibitors

The HGF/Met signaling pathway is over-expressed in many types of cancers and closely related to oncogenesis and metastasis. Thus, we developed novel N-phenylpyrimidin-2-amine derivatives to test their inhibitory activities towards c-Met kinase, and most of the compounds (15a-i, 15o-r, 20 and 34a-c) could inhibit the target with IC₅₀ values from 550.8 nM to 15.0 nM. Subsequently, compound 15b, 15d, 15f, 15i, 15o, 15r, 20, 34a and 34b also showed high antiproliferative activities in c-Met sensitive tumor cell lines (PC-3, Panc-1, HepG2, HCT116 and Caki-1) with IC₅₀ values from 0.53 to 1.37 μM. The lead compound 34a displayed outstanding c-Met inhibitory activity (IC₅₀: 15.0 nM) and antiproliferative activities. Furthermore, 34a also performed favorable pharmacokinetic properties in mice (F%: 59.3) and an acceptable safety profile in preclinical studies. Further docking studies showed a common interaction of 34a with c-Met at the ATP-binding site, which indicated that 34a could be a potential candidate for c-Met inhibitors.

Design, Synthesis, and Biological Evaluation of Dual c-Met/HDAC Inhibitors Bearing 2-Aminopyrimidine Scaffold

A series of c-Met/histone deacetylase (HDAC) bifunctional inhibitors was designed and synthesized by merging pharmacophores of c-Met and HDAC inhibitors. Among them, the most potent compound, 2o, inhibited c-Met kinase and HDACs, with IC50 values of 9.0 and 31.6 nM, respectively, and showed efficient antiproliferative activities against both A549 and HCT-116 cancer cell lines with greater potency than an equimolar mixture of the respective inhibitors of the two enzymes: crizotinib and vorinostat (SAHA). Our study provided an efficient strategy for the discovery of multitargeted antitumor drugs.

Recent Advances in the Discovery of Multitargeted Tyrosine Kinase Inhibitors as Anticancer Agents

The treatment of cancer has been one of the most significant challenges for the medical field. Further research on the signal transduction pathway of tumor cells is driving the rapid development of antitumor agents targeting tyrosine kinases. However, most of the currently approved tyrosine kinase inhibitors based on the "single target/single drug" design are becoming less and less effective in the treatment of complex, heterogeneous, and multigenic cancers; this also results in resistance to chemotherapy. In contrast, multitargeted tyrosine kinase inhibitors (MT-TKIs) can effectively block multiple pathways of intracellular signal transduction. Therefore, they have therapeutic advantages over single-targeted inhibitors and have become a hotspot in antitumor drug research in recent years. This minireview summarizes recent advances in the discovery of MT-TKIs based on their chemical structures. In particular, we describe the kinase inhibitory and antitumor activity of promising compounds, as well as their structure - activity relationships (SARs).

Discovery of Triazolo-pyridazine/-pyrimidine Derivatives Bearing Aromatic (Heterocycle)-Coupled Azole Units as Class II c-Met Inhibitors

Two series of novel triazolo-pyridazine/-pyrimidine derivatives were designed, synthesized, and evaluated for their inhibitory activity against c-Met kinase, as well as three c-Met overexpressed cancer cell lines (A549, MCF-7, and HeLa) and one normal human hepatocytes cell line LO2 in vitro. The pharmacological data indicated that most of the tested compounds showed moderate cytotoxicity, and the most promising compound 12e exhibited significant cytotoxicity against A549, MCF-7, and HeLa cell lines with IC₅₀ values of 1.06 ± 0.16, 1.23 ± 0.18, and 2.73 ± 0.33 μM, respectively. Moreover, the inhibitory activity of compound 12e against c-Met kinase (IC₅₀ = 0.090 μM) was equal to that of Foretinib (IC₅₀ = 0.019 μM). The result of the acridine orange (AO) single staining test demonstrated that compound 12e could remarkably induce apoptosis of A549 cells. The results of apoptosis and cycle distribution of cells showed that compound 12e could induce late apoptosis of A549 cells and stimulate A549 cells arresting in the G0/G1 phase. Structure-activity relationships (SARs), pharmacological results, and docking studies indicated that the introduction of 5-methylthiazole fragment to the five-atom moiety was beneficial for the activity. So far, the existing data indicated that compound 12e may become a potential class II c-Met inhibitor.

Research Progress of Small Molecule VEGFR/c-Met Inhibitors as Anticancer Agents (2016-Present)

Vascular endothelial growth factor receptor 2 (VEGFR-2) binds to VEGFR-A, VEGFR-C and VEGFR-D and participates in the formation of tumor blood vessels, mediates the proliferation of endothelial cells, enhances microvascular permeability, and blocks apoptosis. Blocking or downregulating the signal transduction of VEGFR is the main way to discover new drugs for many human angiogenesis-dependent malignancies. Mesenchymal epithelial transfer factor tyrosine kinase (c-Met) is a high affinity receptor for hepatocyte growth factor (HGF). Abnormal c-Met signaling plays an important role in the formation, invasion and metastasis of human tumors. Therefore, the HGF/c-Met signaling pathway has become a significant target for cancer treatment. Related studies have shown that the conduction of the VEGFR and c-Met signaling pathways has a synergistic effect in inducing angiogenesis and inhibiting tumor growth. In recent years, multi-target small molecule inhibitors have become a research hotspot, among which the research of VEGFR and c-Met dual-target small molecule inhibitors has become more and more extensive. In this review, we comprehensively summarize the chemical structures and biological characteristics of novel VEGFR/c-Met dual-target small-molecule inhibitors in the past five years.

Synthesis of 1,4-diazepinone derivatives via a domino aza-Michael/SN2 cyclization of 1-azadienes with α-halogenoacetamides

A novel cyclization of α-halogenoacetamides with 1-azadienes has been developed for the efficient preparation of monocyclic 1,4-diazepinones in one step under transition metal-free conditions. Various α-halogenoacetamides and 1-azadienes are well tolerated and give the desired products in good to excellent yields. This cyclization also demonstrates potential synthetic utility on a gram-scale and further transformation.

Tandem Prins cyclization for the synthesis of indole fused spiro-1,4-diazocane scaffolds

A tandem Prins strategy has been developed for the first time to produce a novel class of spiro-1,4-diazocane derivatives by the condensation of indole tethered γ-hydroxyolefin with aldehydes using BF₃·OEt₂ at −40 °C in dichloromethane.

Design, synthesis, and biological evaluation of 4-((6,7-dimethoxyquinoline-4-yl)oxy)aniline derivatives as FLT3 inhibitors for the treatment of acute myeloid leukemia

FMS-like tyrosine kinase 3 (FLT3) was an important therapeutic target in acute myeloid leukemia (AML). We synthesized two series of 4-((6,7-dimethoxyquinoline-4-yl)oxy)aniline derivatives possessing the semicarbazide moiety and 2,2,2-trifluoro-N,N'-dimethylacetamide moiety as the linker. The cell proliferation assay in vitro against HL-60 and MV4-11 cell lines demonstrated that most series I compounds containing semicarbazide moiety had more potent than Cabozantinib. Furthermore, the enzyme assay showed that compound 12c and 12g were potent FLT3 inhibitors with IC₅₀ values of 312 nM and 384 nM, respectively. Following that, molecular docking analysis was also performed to determine possible binding mode between FLT3 and the target compound.

Synthesis of N-Pyrrolyl(furanyl)-Substituted Piperazines, 1,4-Dizepanes, and 1,4-Diazocanes

The synthetic potential of 5-bromo-1,1,1-trifluoro-4-methoxypent-3-en-2-one toward the catalyst-free synthesis of N-pyrrolyl(furanyl)-piperazines, 1,4-diazepanes, and 1,4-diazocanes through a telescoped protocol is reported. This three-component one-pot method provided 23 examples with high chemo- and regioselectivity at yields up to 96%.