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Rearranged during transfection (RET), an oncogenic driver, has been found in multiple tumor types and is thus a promising anticancer therapeutic target. Novel selective RET inhibitors (RETi) that can overcome V804 gatekeeper mutations, endowing resistance to multikinase inhibitors (MKI) and, in particular, achieving KDR selectivity, are needed. In addition, the mechanisms underlying RET–inhibition-induced antiproliferative effects in the context of RET addiction are incompletely understood. This study describes a novel selective RETi, SYHA1815, which inhibited the kinase activity of RET wild type and V804 mutant with an IC50 in the subnanomolar to nanomolar range. Notably, SYHA1815 exhibited approximately 20-fold selectivity for RET over KDR, almost equivalent to that of the launched selective inhibitor pralsetinib. SYHA1815 had only a marginal inhibitory effect on cellular KDR signaling at a high (200 nmol/L) concentration, confirming the selectivity over KDR. In addition, SYHA1815 exhibited a favorable selectivity profile, with greater than 100-fold selectivity for RET over 347 other kinases. It exhibited potent antitumor efficacy and overcame V804 mutations in vitro and in vivo by targeting RET. Then, using SYHA1815 as a probe, we found that RET inhibition suppressed RET-driven cell proliferation via G1 cell-cycle arrest through downregulating c-Myc. Furthermore, disruption of c-Myc upon Brd4 inhibitor treatment led to G1 cell-cycle arrest and overrode RET-driven cell proliferation. Moreover, consistent with the marked in vivo efficacy of RET inhibition, the intratumoral c-Myc level was significantly decreased. In summary, SYHA1815 is a promising RETi for RET-aberrant cancer treatment that is currently in a phase I trial.

Because the receptor tyrosine kinase c-Met plays a critical role in tumor growth, metastasis, tumor angiogenesis, and drug resistance, the c-Met axis represents an attractive therapeutic target. Herein, we report the first preclinical characterization of SCC244, a novel, potent, and highly selective inhibitor of c-Met kinase. SCC244 showed subnanomolar potency against c-Met kinase activity and high selectivity versus 312 other tested protein kinases, making it one of the most selective c-Met inhibitors described to date. Moreover, this inhibitor profoundly and specifically inhibits c-Met signal transduction and thereby suppresses the c-Met–dependent neoplastic phenotype of tumor and endothelial cells. In xenografts of human tumor cell lines or non–small cell lung cancer and hepatocellular carcinoma patient-derived tumor tissue driven by MET aberration, SCC244 administration exhibits robust antitumor activity at the well-tolerated doses. In addition, the in vivo antitumor activity of SCC244 involves the inhibition of c-Met downstream signaling via a mechanism of combined antiproliferation and antiangiogenic effects. The results of the current study provide a strong foundation for the clinical investigation of SCC244 in patients with tumors harboring c-Met pathway alterations. Mol Cancer Ther; 17(4); 751–62. ©2017 AACR.

Supplementary Data

Idiopathic pulmonary fibrosis (IPF) is a chronic fatal lung disease with a median survival time of 3‒5 years. Inaccurate diagnosis, limited clinical therapy and high mortality together indicate that the development of effective therapeutics for IPF is an urgent need. In recent years, it was reported that DDRs are potential targets in anti-fibrosis treatment. Based on previous work we carried out further structure modifications and led to a more selective inhibitor 47 by averting some fibrosis-unrelated kinases, such as RET, AXL and ALK. Extensive profiling of compound 47 has demonstrated that it has potent DDR1/2 inhibitory activities, low toxicity, good pharmacokinetic properties and reliable in vivo anti-fibrosis efficacy. Therefore, we confirmed that discoidin domain receptors are promising drug targets for IPF, and compound 47 would be a promising candidate for further drug development.

Receptor tyrosine kinase AXL exerts pivotal roles in cancer cell survival, metastasis, and drug resistance. Pharmacologic or genetic targeting of the aberrant AXL signaling has proven preferable antitumor efficacies in both preclinical and clinical studies, which highlights AXL as an attractive antitumor drug target. By conformational restriction of the anilinopyrimidine

Rearranged during transfection (RET), an oncogenic driver, has been found in multiple tumor types and is thus a promising anticancer therapeutic target. Novel selective RET inhibitors (RETi) that can overcome V804 gatekeeper mutations, endowing resistance to multikinase inhibitors (MKI) and, in particular, achieving KDR selectivity, are needed. In addition, the mechanisms underlying RET–inhibition-induced antiproliferative effects in the context of RET addiction are incompletely understood. This study describes a novel selective RETi, SYHA1815, which inhibited the kinase activity of RET wild type and V804 mutant with an IC50 in the subnanomolar to nanomolar range. Notably, SYHA1815 exhibited approximately 20-fold selectivity for RET over KDR, almost equivalent to that of the launched selective inhibitor pralsetinib. SYHA1815 had only a marginal inhibitory effect on cellular KDR signaling at a high (200 nmol/L) concentration, confirming the selectivity over KDR. In addition, SYHA1815 exhibited a favorable selectivity profile, with greater than 100-fold selectivity for RET over 347 other kinases. It exhibited potent antitumor efficacy and overcame V804 mutations in vitro and in vivo by targeting RET. Then, using SYHA1815 as a probe, we found that RET inhibition suppressed RET-driven cell proliferation via G1 cell-cycle arrest through downregulating c-Myc. Furthermore, disruption of c-Myc upon Brd4 inhibitor treatment led to G1 cell-cycle arrest and overrode RET-driven cell proliferation. Moreover, consistent with the marked in vivo efficacy of RET inhibition, the intratumoral c-Myc level was significantly decreased. In summary, SYHA1815 is a promising RETi for RET-aberrant cancer treatment that is currently in a phase I trial.

Fibroblast growth factor receptor (FGFR) is a promising anticancer target. Currently, most FGFR inhibitors lack sufficient selectivity and have nonnegligible activity against kinase insert domain receptor (KDR), limiting their feasibility due to the serious side effects. Notably, compensatory activation occurs among FGFR1–4, suggesting the urgent need to develop selective pan-FGFR1–4 inhibitors. Here, we explored the antitumor activity of DW14383, a novel irreversible FGFR1–4 inhibitor. DW14383 exhibited equivalently high potent inhibition against FGFR1, 2, 3 and 4, with IC(50) values of less than 0.3, 1.1, less than 0.3, and 0.5 nmol/L, respectively. It is a selective FGFR inhibitor, exhibiting more than 1100-fold selectivity for FGFR1 over recombinant KDR, making it one of the most selective FGFR inhibitors over KDR described to date. Furthermore, DW14383 significantly inhibited cellular FGFR1–4 signaling, inducing G1/S cell cycle arrest, which in turn antagonized FGFR-dependent tumor cell proliferation. In contrast, DW14383 had no obvious antiproliferative effect against cancer cell lines without FGFR aberration, further confirming its selectivity against FGFR. In representative FGFR-dependent xenograft models, DW14383 oral administration substantially suppressed tumor growth by simultaneously inhibiting tumor proliferation and angiogenesis via inhibiting FGFR signaling. In summary, DW14383 is a promising selective irreversible pan-FGFR inhibitor with pan-tumor spectrum potential in FGFR1–4 aberrant cancers, which has the potential to overcome compensatory activation among FGFR1–4.

Receptor-interacting protein kinase 2 (RIPK2) is an essential protein kinase mediating signal transduction by NOD1 and NOD2, which play an important role in regulating immune signalling. In this study, we designed and synthesised a novel series of 4-aminoquinoline-based derivatives as RIPK2 inhibitors. In vitro, compound 14 exhibited high affinity (IC50 = 5.1 ± 1.6 nM) and excellent selectivity to RIPK2 showing in a dendrogram view of the human kinome phylogenetic tree. Bearing favourable lipophilicity and eligible lipophilic ligand efficiency (LipE), compound 14 was selected to investigate cellular anti-inflammatory effect and was identified as a potent inhibitor to reduce the secretion of MDP-induced TNF-α with a dose-dependent manner. Moreover, compound 14 showed moderate stability in human liver microsome. Given these promising results, compound 14 could serve as a favourable inhibitor of RIPK2 for further physiological and biochemical research so as to be used in therapeutic treatment.

Idiopathic pulmonary fibrosis (IPF) is a chronic fatal lung disease with a median survival time of 3-5 years. Inaccurate diagnosis, limited clinical therapy and high mortality together indicate that the development of effective therapeutics for IPF is an urgent need. In recent years, it was reported that DDRs are potential targets in anti-fibrosis treatment. Based on previous work we carried out further structure modifications and led to a more selective inhibitor

Background The interaction between tumor cells and their immunosuppressive microenvironment promotes tumor progression and drug resistance. Thus, simultaneously targeting tumor cells and stromal cells is expected to have synergistic antitumor effects. Herein, we present for the first time a preclinical antitumor investigation of 3D185, a novel dual inhibitor targeting FGFRs, which are oncogenic drivers, and CSF-1R, which is the major survival factor for protumor macrophages. Methods The antitumor characteristics of 3D185 were assessed by a range of assays, including kinase profiling, cell viability, cell migration, immunoblotting, CD8+ T cell suppression, and in vivo antitumor efficacy, followed by flow cytometric and immunohistochemical analyses of tumor-infiltrating immune cells and endothelial cells in nude mice and immune-competent mice. Results 3D185 significantly inhibited the kinase activity of FGFR1/2/3 and CSF-1R, with equal potency and high selectivity over other kinases. 3D185 suppressed FGFR signaling and tumor cell growth in FGFR-driven models both in vitro and in vivo. In addition, 3D185 could inhibit the survival and M2-like polarization of macrophages, reversing the immunosuppressive effect of macrophages on CD8+ T cells as well as CSF1-differentiated macrophage induced-FGFR3-aberrant cancer cell migration. Furthermore, 3D185 inhibited tumor growth via remodeling the tumor microenvironment in TAM-dominated tumor models. Conclusions 3D185 is a promising antitumor candidate drug that simultaneously targets tumor cells and their immunosuppressive microenvironment and has therapeutic potential due to synergistic effects. Our study provides a solid foundation for the investigation of 3D185 in cancer patients, particularly in patients with aberrant FGFR and abundant macrophages, who respond poorly to classic pan-FGFRi treatment. Electronic supplementary material The online version of this article (10.1186/s13046-019-1357-y) contains supplementary material, which is available to authorized users.

Although lung adenocarcinoma patients have benefited from the development of targeted therapy, patients with lung squamous cell carcinoma (SqCC) have no effective treatment due to the complexity and heterogeneity of the disease. Therefore, basing on the genetic analysis of mutations in lung squamous cell carcinoma to design multi-target inhibitors represents a potential strategy for the medical treatment. In this study, through screening an in-house focused library, we identified an interesting indazole scaffold. And following with binding analysis, we elaborated the structure-activity relationship of this hit compound by optimizing four parts guided by the DDR2 enzymatic assay, which resulted in a potent lead compound 10a. We conducted further optimization of dual enzymatic inhibitions towards FGFR1 and DDR2, two important kinases in lung squamous cell carcinoma. Finally, from the cellular antiproliferative activity tests and in vivo pharmacokinetic test, 3-substituted indazole derivative 11k was found to be a promising candidate and subjected to in vivo pharmacology study with the mouse xenograft models, demonstrating profound anti-tumor efficacy. Additional in vitro druglike assessment reinforced that compound 11k could be valuable for SqCC drug development.

The receptor tyrosine kinase Axl plays important roles in promoting cancer progression, metastasis, and drug resistance and has been identified as a promising target for anticancer therapeutics. We used molecular modeling-assisted structural optimization starting with the low micromolar potency compound 9 to discover compound 13c, a highly potent and orally bioavailable Axl inhibitor. Selectivity profiling showed that 13c could inhibit the well-known oncogenic kinase Met with equal potency to its inhibition of Axl superfamily kinases. Compound 13c significantly inhibited cellular Axl and Met signaling, suppressed Axl- and Met-driven cell proliferation, and restrained Gas6/Axl-mediated cancer cell migration or invasion. Furthermore, 13c exhibited significant antitumor efficacy in Axl-driven and Met-driven tumor xenograft models, causing tumor stasis or regression at well-tolerated doses. All these favorable data make 13c a promising therapeutic candidate for cancer treatment.

Rearranged during transfection (RET), an oncogenic driver, has been found in multiple tumor types and is thus a promising anticancer therapeutic target. Novel selective RET inhibitors (RETi) that can overcome V804 gatekeeper mutations, endowing resistance to multikinase inhibitors (MKI) and, in particular, achieving KDR selectivity, are needed. In addition, the mechanisms underlying RET-inhibition-induced antiproliferative effects in the context of RET addiction are incompletely understood. This study describes a novel selective RETi, SYHA1815, which inhibited the kinase activity of RET wild type and V804 mutant with an IC

Axl has emerged as an attractive target for cancer therapy due to its strong correlation with tumor growth, metastasis, poor survival, and drug resistance. Herein, we report the design, synthesis and structure-activity relationship (SAR) investigation of a series of pyrrolo[2,3-d]pyrimidine derivatives as new Axl inhibitors. Among them, the most promising compound 13b showed high enzymatic and cellular Axl potencies. Furthermore, 13b possessed preferable pharmacokinetic properties and displayed promising therapeutic effect in BaF3/TEL-Axl xenograft tumor model. Compound 13b may serve as a lead compound for new antitumor drug discovery.

The ROS1 fusion kinase is an attractive antitumor target. Though with significant clinical efficacy, the well-known first-generation ROS1 inhibitor (ROS1i) crizotinib inevitably developed acquired resistance due to secondary point mutations in the ROS1 kinase. Novel ROS1is effective against mutations conferring secondary crizotinib resistance, especially G2032R, are urgently needed. In the present study, we evaluated the antitumor efficacy of SAF-189s, the new-generation ROS1/ALK inhibitor, against ROS1 fusion wild-type and crizotinib-resistant mutants. We showed that SAF-189s potently inhibited ROS1 kinase and its known acquired clinically resistant mutants, including the highly resistant G2032R mutant. SAF-189s displayed subnanomolar to nanomolar IC(50) values against ROS1 wild-type and mutant kinase activity and a selectivity vs. other 288 protein kinases tested. SAF-189s blocked cellular ROS1 signaling, and in turn potently inhibited the cell proliferation in HCC78 cells and BaF3 cells expressing ROS1 fusion wild-type and resistance mutants. In nude mice bearing BaF3/CD74–ROS1 or BaF3/CD74–ROS1(G2032R) xenografts, oral administration of SAF-189s dose dependently suppressed the growth of both ROS1 wild-type- and G2032R mutant-driven tumors. In a patient-derived xenograft model of SDC4–ROS1 fusion NSCLC, oral administration of SAF-189s (20 mg/kg every day) induced tumor regression and exhibited notable prolonged and durable efficacy. In addition, SAF-189s was more potent than crizotinib and comparable to lorlatinib, the most advanced ROS1i known against the ROS1(G2032R). Collectively, these results suggest the promising potential of SAF-189s for the treatment of patients with the ROS1 fusion G2032R mutation who relapse on crizotinib. It is now recruiting both crizotinib-relapsed and naive ROS1-positive NSCLC patients in a multicenter phase II trial (ClinicalTrials.gov Identifier: NCT04237805).

Receptor tyrosine kinase c-Met is an important antitumor drug target. Triazolotriazine analogues 2-10 were prepared efficiently and evaluated the enzymatic and cellular c-Met activities. Brief structure-activity relationships of triazolotriazine core and CF2-quinoline part were investigated, leading to the discovery of compound 8 with nanomolar enzymatic c-Met activity, and subnanomolar MKN45 and EBC-1 cellular potencies. The proposed binding model of 8 and c-Met unraveled that two canonical hydrogen bonds and a π-π stacking interaction formed between the inhibitor and the ATP binding site of c-Met kinase domain, which accounted for its potent c-Met activities.

Table S1. Some background information of cell lines used in the study. Table S2. Enzymatic kinase activity of the 3D185 and AZD4547. Table S3. Profiling of 3D185 against 372 kinases by Eurofins. Table S4. Anti-proliferative activity of 3D185 in sensitive cell lines. Table S5. Antiproliferative assay used in indicated cell lines in Fig. 2. Table S6. The effect of 3D185 and PLX3397 on cell survival of CSF-1-differentiated or GM-CSF-differentiated murine and human ‘protumor’ macrophages or ‘antitumor’ Mo-DCs/macrophages. Figure S1. The gating strategies for Macrophage, CD8+ T cell, Treg in flow cytometry analyses of tumor-infiltrating immune cells. Figure S2. 3D185 inhibited FGFR1 kinase activity in an ATP-competitive manner and inhibited bFGF-stimulated FGFR signaling in primary HUVECs. Figure S3. The intensity of phosphorylated protein band was quantified and normalized with the corresponding internal control protein band supported for Fig. 2. Figure S4. 3D185 reversed M2-like macrophage-induced CD8+ T cell suppression. Figure S5. Analysis of body weight for tumor-bearing mice and Ki67, CD31expression as well as tumor infiltration CD8+ T and MDSC cell in tumor models. (DOCX 8.29 mb)

Starting from the recently launched FLT3/AXL multi-targeted inhibitor Gilteritinib (5), we conducted a side-chain ring closure medicinal chemistry approach leading to the identification of compound 15c as a highly potent AXL inhibitor in the biochemical and cellular anti-proliferative assays, with IC50 values of 1.2 and 0.3 nM, respectively. Compared with the reference compound 5, our new discovered AXL inhibitor 15c is more potent in both assays.

// Ying Wang 1, * , Zhengsheng Zhan 2, * , Xifei Jiang 3, 4, * , Xia Peng 1 , Yanyan Shen 1 , Fang Chen 2 , Yinchun Ji 1 , Weiren Liu 3, 4 , Yinghong Shi 3, 4 , Wenhu Duan 2 , Jian Ding 1 , Jing Ai 1 , Meiyu Geng 1 1 Division of Anti-Tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R.China 2 Department of Medicinal Chemistry Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, P.R.China 3 Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, P.R.China 4 Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, P.R.China * These authors have contributed equally to this work Correspondence to: Jing Ai, e-mail: jai@simm.ac.cn Meiyu Geng, e-mail: mygeng@simm.ac.cn Keywords: c-Met, kinase inhibitor, Simm530 Received: October 29, 2015 Accepted: April 29, 2016 Published: May 13, 2016 ABSTRACT The aberrant c-Met activation has been implicated in a variety of human cancers for its critical role in tumor growth, metastasis and tumor angiogenesis. Thus, c-Met axis presents as an attractive therapeutic target. Notably, most of these c-Met inhibitors currently being evaluated in clinical trials lack selectivity and target multiple kinases, often accounting for the undesirable toxicities. Here we described Simm530 as a potent and selective c-Met inhibitor. Simm530 demonstrated >2,000 fold selectivity for c-Met compared with other 282 kinases, making it one of the most selective c-Met inhibitors described to date. This inhibitor significantly blocked c-Met signaling pathways regardless of mechanistic complexity implicated in c-Met activation. As a result, Simm530 led to substantial inhibition of c-Met-promoted cell proliferation, migration, invasion, ECM degradation, cell scattering and invasive growth. In addition, Simm530 inhibited primary human umbilical vascular endothelial cell (HUVEC) proliferation, decreased intratumoral CD31 expression and plasma pro-angiogenic factor interleukin-8 secretion, suggesting its significant anti-angiogenic properties. Simm530 resulted in dose-dependent inhibition of c-Met phosphorylation and tumor growth in c-Met-driven lung and gastric cancer xenografts. And, the inhibitor is well tolerated even at doses that achieve complete tumor regression. Together, Simm530 is a potent and highly selective c-Met kinase inhibitor that may have promising therapeutic potential in c-Met-driven cancer treatment.

Aberrant signaling of Axl frequently occurs in many cancer types. Axl activation has been identified as a key trigger in epithelial to mesenchymal transition (EMT), which accounts for acquired drug resistance to many tyrosine kinase inhibitor therapies. It also has been revealed that Axl signaling is associated with immunosuppression. Therefore, Axl inhibitors may present a promising strategy for cancer therapeutics. We have designed and synthesized a series of pyrimidinone Axl inhibitors, and DW17401 was identified as a highly potent, orally available inhibitor against Axl, with IC50 values of 0.9 nM. DW17401 exhibited significant inhibitory effect against Axl driven cell proliferation, with an IC50 value of less than 0.02 nM for BaF3/TEL-AXL cell line. Oral dosing of DW17401 25 mg/kg (QD) resulted in complete tumor regressions in subcutaneous transplanted model of BaF3/TEL-AXL in nude mice. In addition, DW17401 could also inhibited c-Met kinase and c-Met-mediated tumor cell proliferation and growth with high potency, indicated it therapeutic potential in MET aberrant cancer. Of note, DW17401 presented favorable pharmacokinetic parameters on SD rat with a half-life time of 13.8 h and a plasma exposure value of 32647 ng.h/mL (p.o. at 3 mg/kg). All these data indicated that DW17401 was an effective promising Axl inhibitor for cancer treatment. Citation Format: Hefeng Zhang, Xia Peng, Yinchun Ji, Yang Dai, Yanyan Shen, Jing Ai, Wenhu Duan. A potent pyrimidinone Axl inhibitor DW17401 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3051.

To address drug resistance caused by ALK kinase mutations, especially the most refractory and predominant mutation G1202R for the second-generation ALK inhibitor, a series of new diarylaminopyrimidine analogues were designed by incorporating a resorcinol moiety (A-ring) to interact the ALK kinase domain where the G1202R is located. Compound 12d turns out as the most potent with IC 50 values of 1.7, 3.5, and 1.8 nM against ALK wild type, gatekeeper mutant L1196M, and the G1202R mutant, respectively. More importantly, compound 12d has excellent inhibitory effects against the proliferation of BaF3 cells specifically expressing ALK wild type, gatekeeper L1196M, and the most challenging mutant G1202R, with IC 50 values all less than 1.5 nM. Collectively, compound 12d is worthy of further investigation as a new more potent third-generation ALK inhibitor to circumvent drug resistance of both the first-generation and the second-generation inhibitors.

Because the receptor tyrosine kinase c-Met plays a critical role in tumor growth, metastasis, tumor angiogenesis, and drug resistance, the c-Met axis represents an attractive therapeutic target. Herein, we report the first preclinical characterization of SCC244, a novel, potent, and highly selective inhibitor of c-Met kinase. SCC244 showed subnanomolar potency against c-Met kinase activity and high selectivity versus 312 other tested protein kinases, making it one of the most selective c-Met inhibitors described to date. Moreover, this inhibitor profoundly and specifically inhibits c-Met signal transduction and thereby suppresses the c-Met–dependent neoplastic phenotype of tumor and endothelial cells. In xenografts of human tumor cell lines or non–small cell lung cancer and hepatocellular carcinoma patient-derived tumor tissue driven by MET aberration, SCC244 administration exhibits robust antitumor activity at the well-tolerated doses. In addition, the in vivo antitumor activity of SCC244 involves the inhibition of c-Met downstream signaling via a mechanism of combined antiproliferation and antiangiogenic effects. The results of the current study provide a strong foundation for the clinical investigation of SCC244 in patients with tumors harboring c-Met pathway alterations. Mol Cancer Ther; 17(4); 751–62. ©2017 AACR.

Simultaneous blockade of more than one pathway is considered to be a promising approach to overcome the low efficacy and acquired resistance of cancer therapies. Thus, a novel series of c-Met/HDAC bifunctional inhibitors was designed and synthesized by merging pharmacophores of c-Met and HDAC inhibitors. The most potent compound, 2m, inhibited c-Met kinase and HDAC1, with IC50 values of 0.71 and 38 nM, respectively, and showed efficient antiproliferative activities against both EBC-1 and HCT-116 cells with greater potency than the reference drug Chidamide. Western blot analysis revealed that compound 2m inhibited phosphorylation of c-Met and c-Met downstream signaling proteins and increased expression of Ac-H3 and p21 in EBC-1 cells in a dose-dependent manner. Our study presents novel compounds for the further exploration of dual c-Met/HDAC pathway inhibition achieved with a single molecule.

Three series of pyrazolo[3,4-d]pyrimidine derivatives were synthesized and evaluated as RET kinase inhibitors. Compounds 23a and 23c were identified to show significant activity both in the biochemical and the BaF3/CCDC6-RET cell assays. Compound 23c was found to significantly inhibit RET phosphorylation and down-stream signaling in BaF3/CCDC6-RET cells, confirming its potent cellular RET-targeting profile. Different from other RET inhibitors with equal potency against KDR that associated with severe toxicity, 23c did not show significant KDR-inhibition even at the concentration of 1μM. These results demonstrated that 23c is a potent and selective RET inhibitor.

Twenty-two new analogs based on the structure of BMS-777607 were designed, synthesized, and evaluated to determine their biological activities. Compounds bearing a cyclic sulfonamide or α-chloropiperidone scaffold exhibited good activity, which may provide a new basis for further structural optimization. Quinoline-containing analogs exhibited better results than did their counterparts with an aminopyrimidine, aminopyridine, or pyrrolopyridine unit. Two analogs, 22d and 22e, stood out as the most potent c-Met inhibitors with IC50s of 0.9 and 1.7 nM, respectively. These two compounds were more potent than BMS-777607 in enzymatic inhibition and cell proliferation studies.

Both c-Met and VEGFR-2 are important targets for cancer therapies. Here we report a series of potent dual c-Met and VEGFR-2 inhibitors bearing an anilinopyrimidine scaffold. Two novel synthetic protocols were employed for rapid analoguing of the designed molecules for structure-activity relationship (SAR) exploration. Some analogues displayed nanomolar potency against c-Met and VEGFR-2 at enzymatic level. Privileged compounds 3a, 3b, 3g, 3h, and 18a exhibited potent antiproliferative effect against c-Met addictive cell lines with IC50 values ranged from 0.33 to 1.7 μM. In addition, a cocrystal structure of c-Met in complex with 3h has been determined, which reveals the binding mode of c-Met to its inhibitor and helps to interpret the SAR of the analogues.

A series of compounds containing a novel 3-carboxypiperidin-2-one scaffold based on the lead structure BMS-777607 were designed, synthesized and evaluated for their c-Met kinase inhibition and cytotoxicity against MKN45 cancer cell lines. The results indicated that five compounds exhibited significant inhibitory effect on c-Met with IC50 values of 8.6−81 nM and four compounds showed potent inhibitory activity against MKN45 cell proliferation, with IC50s ranging from 0.57−16 μM.

A metabolism-based fine-tuning structure-optimization was conducted to address the oxidative metabolism and hERG blockade of our early ALK inhibitor. Compound 8 was identified showing high potency against both ALK wild type and gatekeeper mutant. In addition to the optimal PK properties and significant cell antiproliferative effects, 8 showed complete tumor growth inhibition at doses of 50 or 10mg/kg once daily in the Karpas299 xenograft model. All these results encouraged the further development of 8 as a potent and orally bioavailable ALK inhibitor.

A series of 2-oxo-1,2-dihydroquinoline-containing c-Met inhibitors were designed, synthesized and evaluated for their in vitro activities targeting c-Met. Most compounds showed high potency against c-Met with IC50 values in the single-digit nM range. Among these compounds, two target compounds, namely 1h and 1n, stood out as the most potent c-Met inhibitors with IC50s of 0.6 and 0.7nM, respectively. And 1a exhibited higher potency than BMS-777607 did with respect to the inhibition of cell proliferation. The introduction of electron-donating substituent was favorable for the activities of the compounds to some extent. Furthermore, molecular docking studies also gave encouraging results that supported this work.

Our early structure–activity relationship study has identified benzo[b]carbazolone 6 as a high potency orally bioavailable ALK inhibitor. Further lead profiling disclosed that 6 is active against both ALK resistant and hot spot-activating mutants, and is also highly potent against RET kinase. Tumor stasis and partial tumor regression were achieved with 6 in both NIH/3T3-EML4-ALK and NIH/3T3-EML4-ALK L1196M xenograft models. Based on the optimal in vitro and in vivo antitumor efficacy, compound 6 is now being profiled further in our preclinical settings as a new orally available ALK/RET dual inhibitor.

c-Met/HGF overexpression has been detected in many human malignancies including tumors which are resistant to anticancer therapy. Disrupting the aberrant c-Met/HGF axis has enjoyed significant progress in both preclinical and clinical antitumor campaign. To eliminate the OCH2-related metabolic deficiency of our previously reported triazolotriazine 2, we synthesized a series of CH2-/CF2-linked triazolotriazines and assessed their c-Met activities, leading to the highly potent compound 23 with IC50 values of 0.24 nM of enzymatic activity in c-Met and 0.85 nM of cellular activity in EBC-1 cancer cell line, as well as with complete tumor regression in EBC-1 xenograft mice model at dose of 25 mg/kg via oral administration. Based on its potent anti-proliferative activities and favorable pharmacokinetic properties, 23 has been selected as a drug candidate for preclinical investigation.

Two series of new analogues were designed by replacing the quinoline scaffold of our earlier lead 2 (zgw-atinib) with quinoxaline and pyrido[2,3-d]pyrimidine frameworks. Moderate c-Met inhibitory activity was observed in the quinoxaline series. Among the pyrido[2,3-d]pyrimidine series, compounds 13a-c possessing an O-linkage were inactive, whilst the N-linked analogues 15a-c retained c-Met inhibitory potency. Highest activity was observed in the 3-nitrobenzyl analog 15b that showed an IC(50) value of 6.5 nM. Further structural modifications based on this compound were undergoing.

A series of 2-aminopyridine-3-carboxamide derivatives against c-Met were designed and synthesized by employing bioisosteric replacement of heterocyclic moieties with the amide bond. The structure-activity relationship (SAR) at various positions of the scaffold was explored. In this study, a promising compound (S)-24o with a c-Met IC(50) of 0.022 μM was identified. The compound exhibited dose-dependent inhibition of the phosphorylation of c-Met as well as downstream signaling in EBC-1 cells. Furthermore, the interactive binding model of (S)-24o with c-Met was elucidated by virtue of a molecular modeling study.

Aberrant c-Met activation plays a critical role in cancer formation, progression and dissemination, as well as in development of resistance to anticancer drugs. Therefore, c-Met has emerged as an attractive target for cancer therapy. The aim of this study was to develop new c-Met inhibitors and elaborate the structure-activity relationships of identified inhibitors. Based on the predicted binding modes of Compounds 5 and 14 in docking studies, a new series of c-Met inhibitor-harboring 3-((1H-pyrrolo[3,2-c]pyridin-1-yl)sulfonyl)imidazo[1,2-a]pyridine scaffolds was discovered. Potent inhibitors were identified through extensive optimizations combined with enzymatic and cellular assays. A promising compound was further investigated in regard to its selectivity, its effects on c-Met signaling, cell proliferation and cell scattering in vitro. The most potent Compound 31 inhibited c-Met kinase activity with an IC50 value of 12.8 nmol/L, which was >78-fold higher than those of a panel of 16 different tyrosine kinases. Compound 31 (8, 40, 200 nmol/L) dose-dependently inhibited the phosphorylation of c-Met and its key downstream Akt and ERK signaling cascades in c-Met aberrant human EBC-1 cancer cells. In 12 human cancer cell lines harboring different background levels of c-Met expression/activation, Compound 31 potently inhibited c-Met-driven cell proliferation. Furthermore, Compound 31 dose-dependently impaired c-Met-mediated cell scattering of MDCK cells. This series of c-Met inhibitors is a promising lead for development of novel anticancer drugs.

Two new sesquiterpenes, sarcandralactones A (1) and B (2), and five new dimeric sesquiterpenoids, sarcandrolides A-E (3-7), along with 10 known compounds were isolated from the whole plants of Sarcandra glabra. Their structures were elucidated on the basis of spectroscopic analysis. Some of the new isolates exhibit significant cytotoxicities when tested against a small panel of tumor cell lines.

A series of imidazo[1,2-a]pyridine derivatives against c-Met was designed by means of bioisosteric replacement. In this study, a selective, potent c-Met inhibitor, 22e was identified, with IC50 values of 3.9 nM against c-Met kinase and 45.0 nM against c-Met-addicted EBC-1 cell proliferation, respectively. Compound 22e inhibited c-Met phosphorylation and downstream signaling across different oncogenic forms in c-Met overactivated cancer cells and model cells. Compound 22e significantly inhibited tumor growth (TGI = 75%) with good oral bioavailability (F = 29%) and no significant hERG inhibition. On the basis of systematic metabolic study, the pathway of all possible metabolites of 22e in liver microsomes of different species has been proposed, and a major NADPH-dependent metabolite 33 was generated by liver microsomes. To block the metabolic site, 42 was designed and synthesized for further evaluation. Taken together, the imidazo[1,2-a]pyridine scaffold showed promising pharmacological inhibition of c-Met and warrants further investigation.

c-Met has emerged as an attractive target for targeted cancer therapy because of its abnormal activation in many cancer cells. To identify high potent and selective c-Met inhibitors, we started with profiling the potency and in vitro metabolic stability of a reported hit 7. By rational design, a novel sulfonylpyrazolo[4,3-b]pyridine 9 with improved DMPK properties was discovered. Further elaboration of π–π stacking interactions and solvent accessible polar moieties led to a series of highly potent and selective type I c-Met inhibitors. On the basis of in vitro and in vivo pharmacological and pharmacokinetics studies, compound 46 was selected as a preclinical candidate for further anticancer drug development.