The discovery of novel imidazo[1,2-a]pyridine derivatives as covalent anticancer agents.

The success of targeted covalent inhibitors (TCIs) for treating cancers has spurred the search for novel scaffolds to install covalent warheads. In our endeavour, using a scaffold hopping strategy, we managed to utilize imidazo[1,2-a]pyridine as the core backbone and explored its potential for the development of covalent inhibitors, therefore, synthesizing a series of novel KRAS G12C inhibitors facilitated by the Groebke-Blackburn-Bienaymè reaction (GBB reaction). Preliminary bio-evaluation screening delivered compound I-11 as a potent anticancer agent for KRAS G12C-mutated NCI-H358 cells, whose effects were further clarified by a series of cellular, biochemical, and molecular docking experiments. These results not only indicate the potential of compound I-11 as a lead compound for the treatment of intractable cancers, but also validate the unique role of imidazo[1,2-a]pyridine as a novel scaffold suitable for the discovery of covalent anticancer agents.

Design, synthesis and biological evaluation of novel indolin-2-one derivatives as potent second-generation TRKs inhibitors.

Tropomyosin receptor kinases (TRKs) are effective targets for anti-cancer drug discovery. The first-generation type I TRKs inhibitors, larotrectinib and entrectinib, exhibit durable disease control in the clinic. The emergence of acquired resistance mediated by secondary mutations in the TRKs domain significantly reduces the therapeutic efficacy of these two drugs, indicating an unmet clinical need. In this study, we designed a potent and orally bioavailable TRK inhibitor, compound 24b, using a molecular hybridization strategy. Compound 24b exhibited significant inhibitory potency against multiple TRK mutants in both biochemical and cellular assays. Furthermore, compound 24b induced apoptosis of Ba/F3-TRKAG595R and Ba/F3-TRKAG667C cells in a dose-dependent manner. Additionally, compound 24b exhibited moderate kinase selectivity. In vitro stability revealed that compound 24b showed excellent plasma stability (t1/2 > 289.1 min) and moderate liver microsomal stability (t1/2 = 44.3 min). Pharmacokinetic studies have revealed that compound 24b is an orally bioavailable TRK inhibitor with a good oral bioavailability of 116.07%. These results indicate that compound 24b be used as a lead molecule for further modifications to overcome drug-resistant mutants of TRK.

Design, synthesis and biological evaluation of pyrazolo[3,4-b]pyridine derivatives as TRK inhibitors.

Tropomyosin receptor kinases (TRKs) are associated with the proliferation and differentiation of cells, and thus their continuous activation and overexpression cause cancer. Herein, based on scaffold hopping and computer-aid drug design, 38 pyrazolo[3,4-b]pyridine derivatives were synthesised. Further, we evaluated their activities to inhibit TRKA. Among them, compound C03 showed acceptable activity with an IC50 value of 56 nM and it inhibited the proliferation of the Km-12 cell line with an IC50 value of 0.304 µM together with obvious selectivity for the MCF-7 cell line and HUVEC cell line. Furthermore, compound C03 possessed good plasma stability and low inhibitory activity to a panel of cytochrome P450 isoforms except CYP2C9. Overall, C03 has potential for further exploration.

Design, synthesis, and biological evaluation of aminopyridine derivatives as novel tropomyosin receptor kinase inhibitors.

Tropomyosin receptor kinase (TRK) is a successful target for the treatment of various cancers caused by NTRK gene fusions. Herein, based on a rational drug design strategy, we designed and synthesized 35 aminopyrimidine derivatives that were shown to be TRKA inhibitors in the enzyme assay, among which compounds C3, C4, and C6 showed potent inhibitory activities against TRKA with IC50 values of 6.5, 5.0, and 7.0 nM, respectively. In vitro antiproliferative activity study showed that compound C3 significantly inhibited the proliferation of KM-12 cells but had weak inhibitory effect on MCF-7 cells and HUVEC cells. The preliminary druggability evaluation showed that compound C3 exhibited favorable liver microsomal and plasma stabilities and had weak or no inhibitory activity against cytochrome P450 isoforms at 10 µM. Compounds C3, C4, and C6 were also selected for ADME (absorption, distribution, metabolism, and elimination) properties prediction and molecular docking studies. Inhibition experiments showed that compound C3 was not selective for TRK subtypes. All results indicated that compound C3 was a useful candidate for the development of TRK inhibitors.

Design, synthesis, and biological evaluation of potent FAK-degrading PROTACs.

FAK mediated tumour cell migration, invasion, survival, proliferation and regulation of tumour stem cells through its kinase-dependent enzymatic functions and kinase-independent scaffolding functions. At present, the development of FAK PROTACs has become one of the hotspots in current pharmaceutical research to solve above problems. Herein, we designed and synthesised a series of FAK-targeting PROTACs consisted of PF-562271 derivative 1 and Pomalidomide. All compounds showed significant in vitro FAK kinase inhibitory activity, the IC50 value of the optimised PROTAC A13 was 26.4 nM. Further, A13 exhibited optimal protein degradation (85% degradation at 10 nM). Meantime, compared with PF-562271, PROTAC A13 exhibited better antiproliferative activity and anti-invasion ability in A549 cells. More, A13 had excellent plasma stability with T1/2 >194.8 min. There are various signs that PROTAC A13 could be useful as expand tool for studying functions of FAK in biological system and as potential therapeutic agents.

Discovery of quinazoline derivatives CZw-124 as a pan-TRK inhibitor with potent anticancer effects in vitro and in vivo.

Herein, we report the discovery process and antitumor activity of the TRK inhibitor CZw-124 (8o), which is a quinazoline derivative. Starting from a PAK4 inhibitor, we used various drug design strategies, including pharmacophore feature supplementation, F-scanning, and blocking metabolic sites, and finally found a TRK inhibitor CZw-124 that is effective in vitro and in vivo. Docking studies and molecular dynamics simulations revealed a possible mode of binding of CZw-124 to TRKA. Biological activity evaluation showed that CZw-124 belongs to a class of pan-TRK inhibitors with moderate kinase selectivity. It inhibited the proliferation and induced the apoptosis of Km-12 cells in vitro by interfering with the phosphorylation of TRKA. Pharmacodynamic evaluation in vivo showed that CZw-124 had a tumor inhibition rate comparable to that of larotrectinib after oral administration of 40 mg/kg/d (tumor growth inhibiton = 71%).

Rational drug design to explore the structure-activity relationship (SAR) of TRK inhibitors with 2,4-diaminopyrimidine scaffold.

Tropomyosin receptor kinase (TRK) is an ideal target for treating cancers caused by the NTRK gene fusion. In this study, more than 60 2,4-diaminopyrimidine derivatives were prepared to understand the structure-activity relationship and confirm the rationality of the pharmacophore model reported previously. Among them, compound 19k was found to be a potent pan-TRK inhibitor that inhibits the proliferation of Km-12 cell lines. Additionally, compound 19k induced the apoptosis of Km-12 cells in a concentration-dependent manner. Western blot analysis revealed that compound 19k inhibited the phosphorylation of TRK to block downstream pathways. Compound 19k also possessed outstanding plasma stability and liver microsomal stability in vitro, with half-lives greater than 289.1 min and 145 min, respectively. Pharmacokinetic studies indicated that the oral bioavailability of compound 19k is 17.4%. These results demonstrate that compound 19k could serve as a novel lead compound for overcoming NTRK-fusion cancers.

Design, synthesis, and biological evaluation of coumarin analogs as novel LSD1 inhibitors.

The abnormal expression of lysine-specific histone demethylase 1 (LSD1) is associated with different cancer types, and it is increasingly recognized as a potential therapeutic target in oncology. Here, utilizing core hopping and conformational restriction strategies, we designed and synthesized a series of coumarin analogs that were shown to be potent LSD1 inhibitors in the enzyme assay. Furthermore, several potent compounds were selected to evaluate their antiproliferative activity on A549 cells and MGC-803 cells with high expression of LSD1. Among them, YX10 showed an anticlonogenic effect on A549 cells and MGC-803 cells, with IC50 values of 1.52 ± 0.16 and 0.98 ± 0.18 µM, respectively. Modeling suggested that the inhibitors would bind to the active site of the protein located around the key residues of Asp555 and Lys661. Meanwhile, a preliminary druggability evaluation showed that compound YX10 showed favorable liver microsomal and moderate plasma stability and weak inhibitory activity against cytochrome P450 isoforms at 10 µM. All the results indicated that compound YX10 could represent a promising lead compound for further development.

Design, synthesis, biological evaluation and pharmacophore model analysis of novel tetrahydropyrrolo[3,4-c]pyrazol derivatives as potential TRKs inhibitors.

The tropomyosin receptor kinases TRKs are responsible for different tumor types which caused by NTRK gene fusion, and have been identified as a successful target for anticancer therapeutics. Herein, we report a potent and selectivity TRKs inhibitor 19m through rational drug design strategy from a micromolar potency hit 17a. Compound 19m significantly inhibits the proliferation of TRK-dependent cell lines (Km-12), while it has no inhibitory effect on TRK-independent cell lines (A549 and THLE-2). Furthermore, kinases selectivity profiling showed that in addition to TRKs, compound 19m only displayed relatively strong inhibitory activity on ALK. These data may indicate that compound 19m has a good drug safety. Partial ADME properties were evaluated in vitro and in vivo. Compound 19m exhibited a good AUC values and volume of distribution and low clearance in the pharmacokinetics experiment of rats. Finally, a pharmacophore model guided by experimental results is proposed. We hope this theoretical model can help researchers find type I TRK inhibitors more efficiently.

Genomic characterization and infectivity of a novel SARS-like coronavirus in Chinese bats.

SARS coronavirus (SARS-CoV), the causative agent of the large SARS outbreak in 2003, originated in bats. Many SARS-like coronaviruses (SL-CoVs) have been detected in bats, particularly those that reside in China, Europe, and Africa. To further understand the evolutionary relationship between SARS-CoV and its reservoirs, 334 bats were collected from Zhoushan city, Zhejiang province, China, between 2015 and 2017. PCR amplification of the conserved coronaviral protein RdRp detected coronaviruses in 26.65% of bats belonging to this region, and this number was influenced by seasonal changes. Full genomic analyses of the two new SL-CoVs from Zhoushan (ZXC21 and ZC45) showed that their genomes were 29,732 nucleotides (nt) and 29,802 nt in length, respectively, with 13 open reading frames (ORFs). These results revealed 81% shared nucleotide identity with human/civet SARS CoVs, which was more distant than that observed previously for bat SL-CoVs in China. Importantly, using pathogenic tests, we found that the virus can reproduce and cause disease in suckling rats, and further studies showed that the virus-like particles can be observed in the brains of suckling rats by electron microscopy. Thus, this study increased our understanding of the genetic diversity of the SL-CoVs carried by bats and also provided a new perspective to study the possibility of cross-species transmission of SL-CoVs using suckling rats as an animal model.