Synthesis and biological evaluation of new pyrazol-4-ylpyrimidine derivatives as potential ROS1 kinase inhibitors

Recent advances in the development of dual ALK/ROS1 inhibitors for non-small cell lung cancer therapy

As a member of the insulin-receptor superfamily, ALK plays an important role in regulating the growth, proliferation, and survival of cells. ROS1 is highly homologous with ALK, and can also regulate normal physiological activities of cells. The overexpression of both is closely related to the development and metastasis of tumors. Therefore, ALK and ROS1 may serve as important therapeutic targets in non-small cell lung cancer (NSCLC). Clinically, many ALK inhibitors have shown powerful therapeutic efficacy in ALK and ROS1-positive NSCLC patients. However, after some time, patients inevitably develop drug resistance, leading to treatment failure. There are no significant drug breakthroughs in solving the problem of drug-resistant mutations. In this review, we summarize the chemical structural features of several novel dual ALK/ROS1 inhibitors, their inhibitory effect on ALK and ROS1 kinases, and future treatment strategies for patients with ALK and ROS1 inhibitor-resistant mutations.

Design, Synthesis and Anticancer Profile of New 4-(1H-benzo[d]imidazol-1-yl)pyrimidin-2-amine-Linked Sulfonamide Derivatives with V600EBRAF Inhibitory Effect

A new series of 4-(1H-benzo[d]imidazol-1-yl)pyrimidin-2-amine linked sulfonamide derivatives 12a–n was designed and synthesized according to the structure of well-established V600EBRAF inhibitors. The terminal sulfonamide moiety was linked to the pyrimidine ring via either ethylamine or propylamine bridge. The designed series was tested at fixed concentration (1 µM) against V600EBRAF, finding that 12e, 12i and 12l exhibited the strongest inhibitory activity among all target compounds and 12l had the lowest IC₅₀ of 0.49 µM. They were further screened on NCI 60 cancer cell lines to reveal that 12e showed the most significant growth inhibition against multiple cancer cell lines. Therefore, cell cycle analysis of 12e was conducted to investigate the effect on cell cycle progression. Finally, virtual docking studies was performed to gain insights for the plausible binding modes of vemurafenib, 12i, 12e and 12l.

Fragment-based modification of 2,4-diarylaminopyrimidine derivatives as ALK and ROS1 dual inhibitors to overcome secondary mutants

In order to explore novel ALK and ROS1 dual inhibitors capable of overcoming crizotinib-resistant mutants, two series of 2,4-diarylaminopyrimidine derivatives were designed, synthesized and evaluated for their in vitro cytotoxic activity. In this work, we retained the 2,4-diarylaminopyrimidine scaffold and derivatize the DAAP scaffold with sulfonyl and acrylamide moieties to extend the structure-activity relationship (SAR) study. To our delight, some compounds exhibited excellent inhibitory activity with a double-digit nanomolar level in MTT assay. Four compounds were selected for enzymic assays further, the results led to the identification of a potent ALK and ROS1 dual inhibitor X-17, with IC₅₀ values of 3.7 nM, 2.3 nM, 8.9 nM and 1.9 nM against ALK, ALK^L1196M, ALK^G1202R and ROS1, respectively. Ultimately, the molecular docking studies on X-17 clearly disclosed reasonable and optimal binding interactions with ALK.

Sulfonamide-based 4-anilinoquinoline derivatives as novel dual Aurora kinase (AURKA/B) inhibitors: Synthesis, biological evaluation and in silico insights

Aurora kinases (AURKs) were identified as promising druggable targets for targeted cancer therapy. Aiming at the development of novel chemotype of dual AURKA/B inhibitors, herein we report the design and synthesis of three series of 4-anilinoquinoline derivatives bearing a sulfonamide moiety (5a-d, 9a-d and 11a-d). The % inhibition of AURKA/B was determined for all target quinolines, then compounds showed more than 50% inhibition on either of the enzymes, were evaluated further for their IC₅₀ on the corresponding enzyme. In particular, compound 9d displayed potent AURKA/B inhibitory activities with IC₅₀ of 0.93 and 0.09 µM, respectively. Also, 9d emerged as the most efficient anti-proliferative analogue in the US-NCI anticancer assay toward the NCI 60 cell lines panel, with broad spectrum activity against different cell lines from diverse cancer subpanels. Docking studies, confirmed that, the sulfonamide SO₂ oxygen was involved in a hydrogen bond with Lys162 and Lys122 in AURKA and AURKB, respectively, whereas, the sulfonamide NH could catch hydrogen bond interaction with the surrounding amino acid residues Lys141, Glu260, and Asn261 in AURKA and Lys101, Glu177, and Asp234 in AURKB. Furthermore, N1 nitrogen of the quinoline scaffold formed an essential hydrogen bond with the hinge region key amino acids Ala213 and Ala173 in AURKA and AURKB, respectively.

Synthesis and biological evaluation of small molecule modulators of CDK8/Cyclin C complex with phenylaminoquinoline scaffold

Background

CDK8/CycC complex has kinase activity towards the carboxyterminal domain of RNA polymerase II, and contributes to the regulation of transcription via association with the mediator complex. Different human malignancies, mainly colorectal and gastric cancers, were produced as a result of overexpression of CDK8/CycC in the mediator complex. Therefore, CDK8/CycC complex represents as a cancer oncogene and it has become a potential target for developing CDK8/CycC modulators.

Methods

A series of nine 4-phenylaminoquinoline scaffold-based compounds 5a-i was synthesized, and biologically evaluated as potential CDK8/CycC complex inhibitors.

Results

The scaffold substituent effects on the intrinsic inhibitory activity toward CDK8/CycC complex are addressed trying to present a novel outlook of CDK8/CycC Complex inhibitors with 4-phenylaminoquinoline scaffold in cancer therapy. The secondary benzenesulfonamide analogues proved to be the most potent compounds in suppressing CDK8/CycC enzyme, whereas, their primary benzenesulfonamide analogues showed inferior activity. Moreover, the benzene reversed sulfonamide analogues were totally inactive.

Discussion

The titled scaffold showed promising inhibitory activity data and there is a crucial role of un/substituted sulfonamido group for CDK8/CycC complex inhibitory activity. Compound 5d showed submicromolar potency against CDK8/CycC (IC₅₀ = 0.639 µM) and it can be used for further investigations and to design another larger library of phenylaminoquinoline scaffold-based analogues in order to establish detailed SARs.

Evolution strategy of ROS1 kinase inhibitors for use in cancer therapy

The abnormal expression of c-ros oncogene1 receptor tyrosine kinase (ROS1) has been identified as clinically actionable oncogenic driver in non-small-cell lung cancer. Since crizotinib was approved by the US FDA for the treatment of advanced ROS1-positive non-small-cell lung cancer, ROS1 kinase has become a promising therapeutic target. Under the guidance of some advanced computer-assisted technologies, such as structure-based drug design, homology modeling and lipophilic efficiency parameters, several potent and selective inhibitors against wild-type and mutant ROS1 were designed and synthesized. In this article, we will review a series of scaffolds targeting ROS1 kinase from the hit-to-drug evolution strategies of their representative compounds and it is hoped that these design strategies would facilitate medicinal chemists to optimize the process of drug design.

Design, synthesis, biological evaluation and molecular modeling of novel 2-amino-4-(1-phenylethoxy) pyridine derivatives as potential ROS1 inhibitors

With the aim of discovering potential and selective inhibitors targeting ROS1 kinase, we rationally designed, synthesized and evaluated two series of novel 2-amino-pyridine derivatives with 1-phenylethoxy at C-3 and C-4 position. The enzymic assays results indicated that six of the new compounds 13b-13d and 14a-14c showed remarkably higher inhibitory activities against ROS1 kinase. The most promising compounds, 13d and 14c displayed the most desired ROS1 inhibitory activity with IC₅₀ values of 440 nM and 370 nM respectively. Furthermore, 13d and 14c displayed ROS1 inhibitory selectivity of about 7-fold and 12-fold, relative to that of ALK sharing about 49% amino acid sequence homology in the kinase domains. They also showed good anti-proliferative effects against ROS1-addicted HCC78 cell lines with the IC₅₀ values of 8.1 μM and 65.3 μM, respectively. Moreover, molecular docking and molecular dynamics simulation studies disclosed that compound 14c and 13d shared similar binding poses with Crizotinib except the selective binding site of ROS1. It also gave a probable molecular explanation for their activity and selectivity, which the methoxyl group in benzene ring was the crucial to the selectivity to ROS1 versus ALK.

Molecular Simulation Studies on the Binding Selectivity of Type-I Inhibitors in the Complexes with ROS1 versus ALK

ROS1 and ALK are promising targets of anticancer drugs for non-small-cell lung cancer. Since they have 49% amide acid sequence homology in the kinases domain and 77% identity at the ATP binding area, some ALK inhibitors also showed some significant responses for ROS1 in the clinical trial, such as the type-I binding inhibitor crizotinib and PF-06463922. As a newly therapeutic target, the selective ROS1 inhibitor is relatively rare. Moreover, the molecular basis for the selectivity of ROS1 versus ALK still remains unclear. In order to disclose the binding preference toward ROS1 over ALK and to aid the design of selective ROS1 inhibitors, the specific interactions and difference of conformational changes in the dual and selective ROS1/ALK inhibitors systems were investigated by molecular dynamics (MD) simulation and principle component analysis (PCA) in our work. Afterward, binding free energies (MM/GBSA) and binding free energies decomposition analysis indicated that the dominating effect of Van der Waals interaction drives the specific binding process of the type-I inhibitor, and residues of the P-loop and the DFG motif would play an important role in selectivity. On the basis of the modeling results, the new designed compound 14c was verified as a selective ROS1 inhibitor versus ALK, and SMU-B was a dual ROS1/ALK inhibitor by the kinase inhibitory study. These results are expected to facilitate the discovery and rational design of novel and specific ROS1 inhibitors.