Yhhu3813 is a novel selective inhibitor of c-Met kinase that inhibits c-Met-dependent neoplastic phenotypes of human cancer cells

Discovery of potent and selective c-Met inhibitors for MET-amplified hepatocellular carcinoma treatment

Hepatocellular carcinoma (HCC) is a prevalent and lethal malignancy worldwide. The MET gene, which encodes receptor tyrosine kinase c-Met, is aberrantly activated in various solid tumors, including non-small cell lung cancer and HCC. In this study, we identified a novel c-Met inhibitor 54 by virtual screening and structural optimization. Compound 54 showed potent c-Met inhibition with an IC50 value of 0.45 ± 0.06 nM. It also exhibited high selectivity among 370 kinases and potent anti-proliferative activity against MET-amplified HCC cells. Moreover, compound 54 displayed significant anti-tumor efficacy in vivo, making it a potential candidate for HCC treatment in future studies.

Novel quinazoline-1,2,3-triazole hybrids with anticancer and MET kinase targeting properties

Oncogenic activation of receptor tyrosine kinases (RTKs) such as MET is associated with cancer initiation and progression. We designed and synthesized a new series of quinazoline derivatives bearing 1,2,3-triazole moiety as targeted anticancer agents. The MET inhibitory effect of synthesized compounds was assessed by homogeneous time-resolved fluorescence (HTRF) assay and western blot analysis. Sulforhodamine B assay was conducted to examine the antiproliferative effects of synthetic compounds against 6 cancer cell lines from different origins including MET-dependent AsPC-1, EBC-1 and MKN-45 cells and also Mia-Paca-2, HT-29 and K562 cells. The growth inhibitory effect of compounds in a three-dimensional spheroid culture was examined by acid phosphatase (APH) assay, while apoptosis induction was evaluated by Annexin V/propidium iodide method. Compound 8c bearing p-methyl benzyl moiety on the triazole ring exhibited the highest MET inhibitory capacity among tested agents that was further confirmed by western blot findings. Derivatives 8c and 8h exhibited considerable antiproliferative effects against all tested cell lines, with more inhibitory effects against MET-positive cells with IC50 values as low as 6.1 μM. These two agents also significantly suppressed cell growth in spheroid cultures and induced apoptosis in MET overexpressing AsPC-1 cells. Moreover, among a panel of 24 major oncogenic kinases, the PDGFRA kinase was identified as a target of 8c and 8h compounds. The docking study results of compounds 8c and 8h were in agreement with experimental findings. The results of the present study suggest that quinazoline derivatives bearing 1,2,3-triazole moiety may represent promising targeted anticancer agents.

Opportunities and challenges of targeting c-Met in the treatment of digestive tumors

At present, a large number of studies have demonstrated that c-Met generally exerts a crucial function of promoting tumor cells proliferation and differentiation in digestive system tumors. c-Met also mediates tumor progression and drug resistance by signaling interactions with other oncogenic molecules and then activating downstream pathways. Therefore, c-Met is a promising target for the treatment of digestive system tumors. Many anti-tumor therapies targeting c-Met (tyrosine kinase inhibitors, monoclonal antibodies, and adoptive immunotherapy) have been developed in treating digestive system tumors. Some drugs have been successfully applied to clinic, but most of them are defective due to their efficacy and complications. In order to promote the clinical application of targeting c-Met drugs in digestive system tumors, it is necessary to further explore the mechanism of c-Met action in digestive system tumors and optimize the anti-tumor treatment of targeting c-Met drugs. Through reading a large number of literatures, the author systematically reviewed the biological functions and molecular mechanisms of c-Met associated with tumor and summarized the current status of targeting c-Met in the treatment of digestive system tumors so as to provide new ideas for the treatment of digestive system tumors.

Trichothecin Inhibits Cancer-Related Features in Colorectal Cancer Development by Targeting STAT3

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that contributes to cancer progression through multiple processes of cancer development, which makes it an attractive target for cancer therapy. The IL-6/STAT3 pathway is associated with an advanced stage in colorectal cancer patients. In this study, we identified trichothecin (TCN) as a novel STAT3 inhibitor. TCN was found to bind to the SH2 domain of STAT3 and inhibit STAT3 activation and dimerization, thereby blocking STAT3 nuclear translocation and transcriptional activity. TCN did not affect phosphorylation levels of STAT1. TCN significantly inhibited cell growth, arrested cell cycle at the G0/G1 phase, and induced apoptosis in HCT 116 cells. In addition, the capacities of colony formation, migration, and invasion of HCT 116 cells were impaired upon exposure to TCN with or without IL-6 stimulation. In addition, TCN treatment abolished the tube formation of HUVEC cells in vitro. Taken together, these results highlight that TCN inhibits various cancer-related features in colorectal cancer development in vitro by targeting STAT3, indicating that TCN is a promising STAT3 inhibitor that deserves further exploration in the future.

Novel Peptide CM 7 Targeted c-Met with Antitumor Activity

Anomalous changes of the cell mesenchymal–epithelial transition factor (c-Met) receptor tyrosine kinase signaling pathway play an important role in the occurrence and development of human cancers, including gastric cancer. In this study, we designed and synthesized a novel peptide (CM 7) targeting the tyrosine kinase receptor c-Met, that can inhibit c-Met-mediated signaling in MKN-45 and U87 cells. Its affinity to human c-Met protein or c-Met-positive cells was determined, which showed specific binding to c-Met with high affinity. Its biological activities against MKN-45 c-Met-positive cells were evaluated in vitro and in vivo. As a result, peptide CM 7 exhibited moderate regulation of c-Met-mediated cell proliferation, migration, invasion, and scattering. The inhibitory effect of peptide CM 7 on tumor growth in vivo was investigated by establishing a xenograft mouse model using MKN-45 cells, and the growth inhibition rate of tumor masses for peptide CM 7 was 62%. Based on our data, CM 7 could be a promising therapeutic peptide for c-Met-dependent cancer patients.

HGF/c-MET: A Promising Therapeutic Target in the Digestive System Cancers

The HGF/c-MET pathway is active in the development of digestive system cancers, indicating that inhibition of HGF/c-MET signaling may have therapeutic potential. Various HGF/c-MET signaling inhibitors, mainly c-MET inhibitors, have been tested in clinical trials. The observed efficacy and adverse events of some c-MET inhibitors were not very suitable for treating digestive system cancers. The development of new HGF/c-MET inhibitors in preclinical studies may bring promising treatments and synergistic combination (traditional anticancer drugs and c-MET inhibitors) strategies provided anacceptable safety and tolerability. Insights into miRNA biology and miRNA therapeutics have made miRNAs attractive tools to inhibit HGF/c-MET signaling. Recent reports show that several microRNAs participate in inhibiting HGF/c-MET signaling networks through antagonizing c-MET or HGF in digestive system cancers, and the miRNAs-HGF/c-MET axis plays crucial and novel roles for cancer treatment. In the current review, we will discuss recent findings about inhibitors of HGF/c-MET signaling in treating digestive system cancers, and how miRNAs regulate digestive system cancers via mediating HGF/c-MET pathway.

The oleocanthal-based homovanillyl sinapate as a novel c-Met inhibitor

The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-Met) signaling axis has gained considerable attention as an attractive molecular target for therapeutic blockade of cancer. Inspired by the chemical structure of S (-)-oleocanthal, a natural secoiridoid from extra-virgin olive oil with documented anticancer activity against c-Met-dependent malignancies, the research presented herein reports on the discovery of the novel olive-derived homovanillyl sinapate (HVS) as a promising c-Met inhibitor. HVS was distinguished for its remarkable potency against wild-type c-Met and its oncogenic variant in cell-free assays and confirmed by in silico docking studies. Furthermore, HVS substantially impaired the c-Met-mediated growth across a broad spectrum of breast cancer cells, while similar treatment doses had no effect on the non-tumorigenic mammary epithelial cell growth. In addition, HVS caused a dose-dependent inhibition of HGF-induced, but not epidermal growth factor (EGF)-induced, cell scattering in addition to HGF-mediated migration, invasion, and 3-dimensional (3D) proliferation of tumor cell spheroids. HVS treatment effects were mediated via inhibition of ligand-mediated c-Met activation and its downstream mitogenic signaling and blocking molecular mediators involved in cellular motility across different cellular contexts. An interesting feature of HVS is its good selectivity for c-Met and Abelson murine leukemia viral oncogene homolog 1 (ABL1) when profiled against a panel of kinases. Docking studies revealed interactions likely to impart high dual affinity for both ABL1 and c-Met kinases. HVS markedly reduced tumor growth, showed excellent pharmacodynamics, and suppressed cell proliferation and microvessel density in an orthotopic model of triple negative breast cancer. Collectively, the present findings suggested that the oleocanthal-based HVS is a promising c-Met inhibitor lead entity with excellent therapeutic potential to control malignancies with aberrant c-Met activity.

Isolation and characterization of anti c-met single chain fragment variable (scFv) antibodies

The receptor tyrosine kinase (RTK) Met is the cell surface receptor for hepatocyte growth factor (HGF) involved in invasive growth programs during embryogenesis and tumorgenesis. There is compelling evidence suggesting important roles for c-Met in colorectal cancer proliferation, migration, invasion, angiogenesis, and survival. Hence, a molecular inhibitor of an extracellular domain of c-Met receptor that blocks c-Met-cell surface interactions could be of great thera-peutic importance. In an attempt to develop molecular inhibitors of c-Met, single chain variable fragment (scFv) phage display libraries Tomlinson I + J against a specific synthetic oligopeptide from the extracellular domain of c-Met receptor were screened; selected scFv were then characterized using various immune techniques. Three c-Met specific scFv (ES1, ES2, and ES3) were selected following five rounds of panning procedures. The scFv showed specific binding to c-Met receptor, and significantly inhibited proliferation responses of a human colorectal carcinoma cell line (HCT-116). Moreover, anti- apoptotic effects of selected scFv antibodies on the HCT-116 cell line were also evaluated using Annexin V/PI assays. The results demonstrated rates of apoptotic cell death of 46.0, 25.5, and 37.8% among these cells were induced by use of ES1, ES2, and ES3, respectively. The results demonstrated ability to successfully isolate/char-acterize specific c-Met scFv that could ultimately have a great therapeutic potential in immuno-therapies against (colorectal) cancers.

Discovery of a new series of imidazo[1,2-a]pyridine compounds as selective c-Met inhibitors

AIM

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.

METHODS

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.

RESULTS

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.

CONCLUSION

This series of c-Met inhibitors is a promising lead for development of novel anticancer drugs.

Design and optimization of a series of 1-sulfonylpyrazolo[4,3-b]pyridines as selective c-Met inhibitors

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.

Small-molecule inhibitors of the receptor tyrosine kinases: promising tools for targeted cancer therapies

Chemotherapeutic and cytotoxic drugs are widely used in the treatment of cancer. In spite of the improvements in the life quality of patients, their effectiveness is compromised by several disadvantages. This represents a demand for developing new effective strategies with focusing on tumor cells and minimum side effects. Targeted cancer therapies and personalized medicine have been defined as a new type of emerging treatments. Small molecule inhibitors (SMIs) are among the most effective drugs for targeted cancer therapy. The growing number of approved SMIs of receptor tyrosine kinases (RTKs) i.e., tyrosine kinase inhibitors (TKIs) in the clinical oncology imply the increasing attention and application of these therapeutic tools. Most of the current approved RTK-TKIs in preclinical and clinical settings are multi-targeted inhibitors with several side effects. Only a few specific/selective RTK-TKIs have been developed for the treatment of cancer patients. Specific/selective RTK-TKIs have shown less deleterious effects compared to multi-targeted inhibitors. This review intends to highlight the importance of specific/selective TKIs for future development with less side effects and more manageable agents. This article provides an overview of: (1) the characteristics and function of RTKs and TKIs; (2) the recent advances in the improvement of specific/selective RTK-TKIs in preclinical or clinical settings; and (3) emerging RTKs for targeted cancer therapies by TKIs.

SOMCL-863, a novel, selective and orally bioavailable small-molecule c-Met inhibitor, exhibits antitumor activity both in vitro and in vivo

Deregulation of HGF/c-Met signaling and its driven neoplastic phenotype are associated with a variety of human malignancies. We herein reported SOMCL-863 as a novel selective c-Met inhibitor which effectively abrogated c-Met signaling pathways, thereby leading to substantial impairment of c-Met-dependent cell proliferation, migration, invasion, cell scattering and invasive growth. In EBC-1 and NCI-H1993 xenografts, SOMCL-863 exerted significant anti-tumor efficacy through anti-proliferative effects and antiangiogenic mechanisms, including reduction of tumor cell proliferation and reductions of microvessel density and secretion of proangiogenic factor IL-8. Together with the optimal pharmacokinetic properties, SOMCL-863 is a promising candidate worthy for further evaluation as a treatment of c-Met-driven human cancers.

SOMG-833, a novel selective c-MET inhibitor, blocks c-MET-dependent neoplastic effects and exerts antitumor activity

The hepatocyte growth factor/c-MET signaling axis plays an important role in tumor cell proliferation, metastasis, and tumor angiogenesis, and therefore presents as an attractive target for cancer therapy. Notably, most small-molecule c-MET inhibitors currently undergoing clinical trials are multitarget inhibitors with the unwanted inhibition of additional kinases, often accounting for undesirable toxicity. Here, we discovered SOMG-833 [3-(4-methylpiperazin-1-yl)-5-(3-nitrobenzylamino)-7-(trifluoromethyl) quinoline] as a potent and selective small-molecule c-MET inhibitor, with an average IC50 of 0.93 nM against c-MET, over 10,000-fold more potent compared with 19 tyrosine kinases, including c-MET family members and highly homologous kinases. SOMG-833 strongly suppressed c-MET-mediated signaling transduction regardless of mechanistic complexity implicated in c-MET activation, including MET gene amplification, MET gene fusion, and HGF-stimulated c-MET activation. In a panel of 24 human cancer or genetically engineered model cell lines, SOMG-833 potently inhibited c-MET-driven cell proliferation, whereas cancer cells lacking c-MET activation were markedly less sensitive (at least 15-fold) to the treatment. SOMG-833 also suppressed c-MET-mediated migration, invasion, urokinase activity, and invasive growth phenotype. In addition, inhibition of primary human umbilical vascular endothelial cell (HUVEC) proliferation and downregulation of plasma proangiogenic factor interleukin-8 secretion resulted from SOMG-833 treatment, suggesting its significant antiangiogenic properties. Together, these results led to the remarkable antitumor efficacy of SOMG-833 in vivo, as demonstrated in c-MET-dependent NIH-3T3/TPR-MET, U-87MG, and EBC-1 xenograft models. Collectively, our results suggested SOMG-833 as a promising candidate for highly selective c-MET inhibition and a powerful tool to investigate the sole role of MET kinase in cancer.