C-met Gene Research Articles

Comparison of the c-MET gene amplification between primary tumor and metastatic lymph nodes in non-small cell lung cancer.

e23138 Background: Activation of c-MET lead to a wide range of biological activities. MET has recently been identified as a novel promising target in NSCLC, some c-MET inhibitors have been developed. The primary aim of this study was to evaluate the c-MET amplification status in advanced NSCLC and compare the consistency of c-MET amplification analyses in metastatic lymph nodes and tumor tissue.Methods: Real-time fluorescent quantitative polymerase chain reaction was used to test the tumor tissues in 368 patients of NSCLCs and 178 paired metastatic lymph nodes samples and compared the amplifications consistency inmetastatic lymph nodesand tissue samples, and analyzed the correlation between c-MET gene amplification and clinical characteristics of patients. Another 5 cases of normal lung tissue were taken as negative control.Results: The c-MET gene amplification rate was 8.97%(33/368) in tumor tissues . Of the178 paired cases, c-MET gene amplification was positive in 7.95%(15/178) cancerous tissuesand18.54%(33/178) in metastatic lymph nodes; Of these patients,13 were positive in the two kinds of samples. 20 cases in the paired group were detected positive c-MET in metastatic lymph nodes but was negative in cancerous tissues; 2 cases in the paired group were detected positive c-MET gene amplification in cancerous tissues but was negative in metastatic lymph nodes,there were statistically significant differences between the two samples (χ2= 45.536, P < 0.001). c-MET gene amplification was detected more in metastatic lymph nodes than the primary cancerous tissue. Consistency was evaluated by consistency test(Kappa = 0.482, P < 0.001).When lymph nodes were used as surrogate samples of primary cancerous tissues, sensitivity was86.67%, the specificity was 87.69%.Conclusions: More c-MET gene amplification positive were detected in metastatic lymph nodes compare with the primary cancerous tissue. c-MET gene amplification detected in lymph node metastases could screen more patients suitable for TKI therapy. Lymph node Metastasis can predict the c-MET gene amplification of primary tumor, and guide the clinical use of gene targeted drugs.

Effects of small interfering RNA silencing metastasis-associated in colon cancer-1 gene on the proliferation, migration and invasion of liver cancer cells

Objective To investigate the effects of small interfering RNA (siRNA) silencing metastasis-associated in colon cancer-1 (MACC1) gene on the proliferation, migration and invasion of liver cancer cells, and the possible mechanism. Methods HepG2 cells were cultured. According to the different transfectants, the cells were divided into siRNA-MACC1 group, siRNA-NC group and blank control group. The cell proliferations in the different transfected groups were measured by methyl thiazol tetrazolium (MTT) assay. The cell apoptosis in the different transfected groups was examined by flow cytometry. The cell migration and invasion abilities in the different transfected groups were tested by Transwell methods. The expression levels of MACC1, hepatocyte growth factor (HGF) and c-Met genes in the different transfected groups were detected by real-time fluorescent quantitative polymerase chain reaction(FQ-PCR). The expression levels of MACC1, HGF, c-Met, MEK, phosphorylated MEK (p-MEK), extracellular signal-regulated kinase (ERK) and phosphorylated ERK (p-ERK) proteins in the different transfected groups were detected by Western blotting. Results (1) MTT results showed that absorptivity (A) values in the siRNA-MACC1 group at 24, 48, 72 and 96 h (0.27±0.05, 0.36±0.06, 0.46±0.05, 0.58±0.07) were lower than the siRNA-NC group (0.39±0.06, 0.47±0.05, 0.64±0.07, 0.75±0.08) and blank control group (0.41±0.05, 0.49±0.07, 0.62±0.06, 0.77±0.09), the differences were statistically significant (F=25.945, 32.286, 40.264, 38.165, P=0.000, 0.000, 0.000, 0.000). (2) Flow cytometry results showed that the apoptosis rate in the siRNA-MACC1 group was (13.52±2.61)%, which was significantly higher than the siRNA-NC group and blank control group [(4.94±1.84)%, (5.10±2.13)%, F=73.918, P=0.000]. (3) The number of migration cells and the number of invasive cells in the siRNA-MACC1 group (73.62±12.71, 59.23±11.53) were significantly lower than those in the siRNA-NC group and blank control group (98.53±14.22, 85.44±13.12 and 102.51±15.13, 87.62±14.24, F=11.149, 9.500, P=0.000, 0.000). (4) Compared with siRNA-NC group and blank control group, the relative expression levels of MACC1, HGF and c-Met mRNA in the siRNA-MACC1 group were significantly lower than the siRNA-NC group and blank control group (F=51.235, 137.507, 139.708, P=0.000, 0.000, 0.000). (5) Compared with the siRNA-NC group and blank control group, the relative expression levels of MACC1, HGF, c-Met, p-MEK and p-ERK proteins in the siRNA-MACC1 group were decreased (F=49.803, 33.564, 24.391, 228.400, 137.410, P=0.000, 0.000, 0.000, 0.000, 0.000), while the the relative expression levels of MEK and ERK proteins were increased (F=12.751, 23.829, P=0.000, 0.000). Conclusion Specific inhibition of MACC1 gene expression in HepG2 cells could effectively inhibit cell proliferation, decrease cell migration and invasion, and induce cell apoptosis. The mechanism might be related to HGF/Met and MEK/ERK signaling pathways. Key words: Liver cancer; Metastasis-associated in colon cancer-1; Small interfering; Biological characteristics

Establishment of patient-derived gastric cancer xenografts: a useful tool for preclinical evaluation of targeted therapies involving alterations in HER-2, MET and FGFR2 signaling pathways

BackgroundTargeted therapies are emerging treatment options for gastric cancer (GC). Patient-derived tumor xenograft(PDX) models of GC closely retain the features of the original clinical cancer, offering a powerful tool for preclinical drug efficacy testing. This study aimed to establish PDX GC models, and explore therapeutics targeting Her2, MET(cMet), and FGFR2, which may assist doctor to select the proper target therapy for selected patients.MethodsGC tissues from 32 patients were collected and implanted into immuno-deficient mice. Using immunohistochemistry(IHC) and fluorescent in-situ hybridization (FISH), protein levels and/or gene amplification of Her2, cMet and FGFR2 in those tissues were assessed. Finally, anti-tumor efficacy was tested in the PDX models using targeted inhibitors.ResultsA total of 9 passable PDX models were successfully established from 32 gastric cancer xenograft donors, consisting of HER2,cMet and FGFR2 alterations with percentages of 4(12.5%), 8(25.0%) and 1(3.1%) respectively. Crizotinib and AZD4547 exerted marked antitumor effects exclusively in PDX models with cMet (G30,G31) and FGFR2(G03) amplification. Interestingly, synergistic antitumor activity was observed in G03 (FGFR2-amplifed and cMet non-amplified but IHC [2+]) with simultaneous treatment with Crizotinib and ADZ4547 at day 30 post-treatment. Further in vitro biochemistry study showed a synergistic inhibition of the MAPK/ERK pathway. HER2,cMet and FGFR2 alterations were found in 17 (10.4%), 32(19.6%) and 6(3.7%) in a group of 163 GC patients, and cMet gene amplification or protein overexpression(IHC 3+) was associated with poor prognosis.ConclusionsThese PDX GC models provide an ideal platform for drug screening and evaluation. GC patients with positive cMet or FGFR2 gene amplification may potentially benefit from cMet or FGFR2 targeted therapies or combined targeted therapy.

MET Amplification and Response to MET Inhibitors in Stage IV Lung Adenocarcinoma

Background: Non-small-cell lung cancers with MET amplification may respond to c-MET inhibitors. Methods: We examined lung adenocarcinoma patients for mutations and amplification status of epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), ROS, MET. The clinical characteristics of patients with MET amplification and their responses to MET inhibitor therapy were studied. Results: Of the 76 patients analyzed, 5 were positive for c-MET gene amplification and 4 cases showed an intermediate result. For 12 patients who were EGFR positive, a c-MET analysis on secondary biopsy tissue was performed following disease progression. All 5 c-MET-positive patients were men. The age range in the study was 34-83 years. 4 of the 5 patients were started on crizotinib. 2 of these cases were positive following tyrosine kinase inhibitor therapy. 3 patients showed a response. 1 patient showed no response and was later found to have a concurrent T790M mutation. Conclusions: There are 2 categories of MET gene amplification in lung cancer patients, de novo and that secondary to TKI therapy. These patients can benefit from MET inhibitor therapy. Dual mechanisms of resistance, EGFR T790M mutation and c-MET amplification after TKI therapy, may suggest a poor prognosis.

Molecular mechanisms of activating c-MET in KSHV+ primary effusion lymphoma.

The oncogenic Kaposi's sarcoma–associated herpesvirus (KSHV) is a principal causative agent of primary effusion lymphoma (PEL), which is mostly seen in immunosuppressed patients. PEL is a rapidly progressing malignancy with a median survival time of approximately 6 months even under the conventional chemotherapy. We recently report that the hepatocyte growth factor (HGF)/c-MET pathway is highly activated in PEL cells and represents a promising therapeutic target (Blood. 2015;126(26):2821-31). However, the underlying mechanisms of c-MET activation within PEL cells remain largely unknown. To solve this puzzle, here we have utilized the next generation sequencing (NGS) based bioinformatics approach to investigate the genomic landscape of the c-MET gene and we found that there's no single nucleotide variations (SNVs) occurred in the c-MET genomic regions in a cohort of PEL samples. Consistently, Sanger sequencing analysis of frequently mutated exons such as exon 10, 14 and 19 shows no mutation of these c-MET exons in PEL cell-lines, which further supports the notion that mutations are not the major mechanism responsible for c-MET activation in PEL. Further, we found that a transmembrane receptor protein, Plexin-B1, is expressed in PEL cell-lines, which is required for c-MET-mediated PEL cell survival via direct protein interaction.

Understanding c-MET signalling in squamous cell carcinoma of the head & neck.

c-MET is a membrane spanning receptor tyrosine kinase for hepatocyte growth factor (HGF) also termed scatter factor. Transmitting signals from mesenchymal to epithelial cells, the HGF/c-MET axis mediates a range of biological processes that stimulate proliferation, motility, invasiveness, morphogenesis, apoptosis, and angiogenesis. Aberrant c-MET signal transduction favours tumorigenesis with the acquisition of invasive and metastatic phenotypes. Biological functions of c-MET may strongly vary according to microenvironmental changes, which occur at different stages of tumorigenesis and include also HGF/c-MET activation in stromal cells. In this review, we focused on abnormalities in non-nasopharyngeal squamous cell carcinoma of the head & neck. While the prevalence of c-MET mutations and amplifications ranges 0-25%, c-MET upregulation can be found in the majority of squamous head & neck carcinomas. Despite marked heterogeneity in published scoring methods, immunohistochemical overexpression of c-MET has been typically linked to advanced stages and associated with impaired survival and/or resistance to radiotherapy, chemoradiotherapy, and cetuximab. Experimental studies in cell lines and patient-derived xenografts using various c-MET antagonists (both as single-agents and in combination with cytotoxic and epidermal growth factor receptor [EGFR]-directed agents) yielded promising results, albeit benefit in clinical trials remains to be demonstrated. Consequently, selecting more active agents and integrating them effectively in studies, which incorporate predictive biomarkers such as c-MET gene mutations, amplifications, and overexpression, remains challenging. Further investigations should increase emphasis on disentangling the role of tumour-stromal interactions and analyse their potential as modifiers of drug response.

Alterations in transcription and protein expressions of HCC-related genes in HepG2 cells caused by microcystin-LR

Microcystin-LR (MC-LR) is the most common and toxic hepatotoxin and it could induce human hepatitis and hepatocellular carcinoma (HCC) via the route of drinking water. The aim of the present study was to determine the expressions of oncogenes c-fos, c-jun, c-myc, c-met, and N-ras and tumor suppressor gene PTEN in HepG2 cells following MC-LR-exposure to understand the possible mechanism of MC-LR-related human primary liver cancer. The results of qPCR and Western blotting showed that MC-LR-exposure at non- or sub-cytotoxic concentrations promoted the expressions of oncogenes c-fos, c-jun, c-myc, c-met, and N-ras while suppressed tumor-suppressor gene PTEN in HepG2 cells at both transcription and protein levels. This result suggests that HCC-related genes may be involved in human hepatitis and primary liver cancer caused by MC-LR. The work might be useful for evaluating the human health risk resulted from the long-term of MC-LR-exposure at low dose via drinking water route.

50P Droplet digital PCR measurement of c-Met gene amplification in plasma cell free DNA in patients with advanced NSCLC

50P Droplet digital PCR measurement of c-Met gene amplification in plasma cell free DNA in patients with advanced NSCLC

50P Droplet digital PCR measurement of c-Met gene amplification in plasma cell free DNA in patients with advanced NSCLC

50P Droplet digital PCR measurement of c-Met gene amplification in plasma cell free DNA in patients with advanced NSCLC

Profiling of cMET and HER Family Receptor Expression in Pancreatic Ductal Adenocarcinomas and Corresponding Lymph Node Metastasis to Assess Relevant Pathways for Targeted Therapies: Looking at the Soil Before Planting the Seed.

Comprehensive assessment of cMET and HER family receptor tyrosine kinases expression, changes of expression during metastatic progression, amplification status of the MET gene, and correlations with patient characteristics in pancreatic ductal adenocarcinoma (PDAC) was conducted. We investigated 56 PDACs and corresponding lymph node metastases for HER1 to HER4 and cMET expression by immunohistochemistry, as well as cMET gene copy numbers by chromogenic in situ hybridization. Of all receptor tyrosine kinases evaluated, cMET expression was highest with 46.5% of tumors showing moderate or strong expression and a weak correlation with gene copy number status (P = 0.04; Spearman ρ = 0.28). cMET expression was increased in metastases. In contrast, expression levels of HER family receptors were generally low both in primaries and metastases. A weak yet significant correlation of HER1 and cMET expression levels was observed (P < 0.001; Spearman ρ = 0.44) and HER1 was often present in poorly differentiated tumors (G3, P = 0.049). Our data suggest that cMET might constitute an interesting molecule for combining targeted and chemotherapeutic approaches in PDAC, because expression is frequent and increased during metastatic progression. In PDAC, cMET protein expression might be a more useful stratification biomarker than cMET gene amplification, which does not seem to be its primary regulator.

Abstract 963: Epigenetic silencing of miR-199a-3p is associated with increased cell survival, enhanced cell motility, and sensitivity to tivantinib through regulation of c-Met expression in hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and can act as tumor suppressors or oncogenes. To identify miRNA involved in the development of HCC, we performed a genome-wide miRNA gene expression analysis using the human miRNA microarray (Agilent) in paired tumor and non-tumor tissues from patients with primary HCC. The array-based miRNA expression profiles were validated by quantitative PCR. We also screened for genes with promoter DNA hypermethylation using a genome-wide DNA methylation microarray analysis (the Illumina HumanMethylation27 BeadChip) in primary HCCs. We found that miR-214-3p, miR-199a-5p, and miR-199a-3p were significantly down-regulated by aberrant promoter hypermethylation in HCC tumors. The c-Met gene was identified as the direct target of miR-199a-3p. Our study showed that reduced expression of miR-199a-3p was associated with increased cell survival through the c-Met/Akt pathway and enhanced cell motility through phosphorylation of FAK. The transfection of miR-199a-3p mimic reduced the expression of c-Met and enhanced the sensitivity to the c-Met inhibitor tivantinib in HCC cells. In conclusion, our results suggest that epigenetic silencing of tumor suppressor miR-199a-3p may be involved in hepatocarcinogenesis through regulation of c-Met expressionand and be associated with the sensitivity to tivantinib. Citation Format: Kohichiroh Yasui, Akira Tomie, Naoto Iwai, Tomoko Kitaichi, Osamu Dohi, Yasuyuki Gen, Yoshito Itoh. Epigenetic silencing of miR-199a-3p is associated with increased cell survival, enhanced cell motility, and sensitivity to tivantinib through regulation of c-Met expression in hepatocellular carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 963.

Abstract 747: Paracrine c-MET/HGF HCC PDX: evaluation of a biologics targeting c-MET

Abstract The interaction between the c-MET tyrosine kinase receptor (RTK) on the surface of cancer cells with its ligand, hepatocyte growth factor (HGF) secreted from surrounding tumor stroma, results in paracrine signal transduction in cancer cells to promote growth, invasion, angiogenesis and metastases. c-MET gene amplification/over-expression, or activating mutations, frequently function as oncogenic driver in several types of cancers. c-MET is thus considered a key target(1) for both TKIs or biologics. However, lack of suitable animal models has represented an obstacle for the development of new cMET inhibitors. While patient derived xenografts (PDXs) mirror patients’ histopathological/genetic profiles(2-6), they usually lose human stroma, the source of HGF; moreover the HGF originated from murine stroma is incapable of triggering a paracrine signaling because of lack of cross reactivity with the human c-MET. Some PDX grow independent of paracrine mechanisms because of their constitutive c-MET activation by the presence of activating mutations, gene amplification or autocrine signaling, and can be used to evaluate the efficacy of TKIs(5, 7, 8). However they are not suitable to assess biologics, e.g. antibodies disrupting receptor-ligand interaction. Alternatively it is possible to grow tumors in hu-HGF-transgenic immunocompromised mice (humanization) where an artificial paracrine signaling is created. Interestingly, we have identified a unique HCC-PDX, LI0801, which maintains human stroma throughout passages, as demonstrated by immunochemistry staining for human vimentine and human HGF, both markers of stromal components(7, 8). The mechanisms of human stroma maintenance in this PDXremain unclear. We showed that LI0801 responds to different TKIs(7, 8). In addition we evaluated the efficacy of an anti-human c-MET monoclonal antibody in reducing tumor burden in LI0801, and we were able to demonstrate great tumor response to anti-human c-MET antibody, which is significantly more effective than crizotinib. To the best of our knowledge, LI0801 is the first paracrine c-MET PDX reported, and represents an important model to study paracrine cMET/HGF signaling and to evaluate new c-MET inhibitors, both TKIs, and biologics.

Abstract 4663: Combination of c-Met inhibitor tepotinib (MSC2156119J) and a third-generation EGFR inhibitor can overcome double resistance mediated by EGFR T790M mutation and c-Met amplification in non-small cell lung cancer models

Abstract In clinical practice, acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) in EGFR-mutant non-small cell lung cancer (NSCLC) causes EGFR TKI treatment failure. Several resistance mechanisms have been identified; EGFR T790M mutation and aberrant activation of c-Met through c-Met gene amplification and/or HGF upregulation are the two most common mechanisms. We have previously shown that combining the highly selective c-Met inhibitor tepotinib with 1st or 2nd-generation EGFR TKIs overcomes gefitinib resistance caused only by c-MET amplification. Third-generation EGFR TKIs such as rociletinib have been developed specifically to overcome T790M-mediated resistance to EGFR TKIs. We hypothesized that combining a 3rd-generation EGFR TKI with tepotinib could overcome resistance to a 1st or 2nd-generation EGFR TKI (e.g. gefitinib) regardless of the mechanism of resistance. We assessed the efficacy of tepotinib and a Merck-synthesized version of rociletinib (MSR) as monotherapy or in combination in a NSCLC cell line xenograft model (HCC827-GR-T790M) with an EGFR del 19 mutation, c-Met amplification, and exogenous T790M expression, and in a patient-derived xenograft model (DFCI081) with an EGFR del 19 mutation and c-Met amplification, but not a T790M mutation. Single-agent tepotinib, erlotinib, and afatinib did not show antitumor activity in HCC827-GR-T790M xenografts and tumors progressed on treatment (median tumor volume [TV] changes &amp;gt;73%). The combinations of tepotinib + erlotinib and tepotinib + afatinib delayed tumor regrowth more than single-agent therapy, but were no more effective than single-agent MSR. In contrast, the combination of tepotinib + MSR had strong antitumor activity in this model with double resistance due to c-Met amplification and exogenous T790M expression, resulting in complete tumor regression (median TV change -97%). In the patient-derived xenograft model DFCI081, tumors progressed under single-agent therapy with the EGFR TKIs erlotinib, afatinib, and MSR, as expected given that this cell line expresses c-Met. In contrast, tepotinib induced complete tumor regression as monotherapy and when combined with each of the EGFR TKIs (median TV change -100%). Complete regression was maintained until the end of the 60-day observation period after treatment termination. These findings are compatible with the hypothesis that combining tepotinib with a 3rd-generation EGFR TKI to overcome double resistance to 1st and 2nd-generation TKIs mediated by T790M and c-Met in NSCLC is more effective than using either agent alone. Furthermore, whereas EGFR TKIs were not effective in tumor models showing c-Met amplification and EGFR del 19 mutation but not T790M mutation, ie resistance is c-Met mediated, tepotinib monotherapy induced complete tumor regression. Citation Format: Manja Friese-Hamim, Giuseppe Locatelli, Friedhelm Bladt. Combination of c-Met inhibitor tepotinib (MSC2156119J) and a third-generation EGFR inhibitor can overcome double resistance mediated by EGFR T790M mutation and c-Met amplification in non-small cell lung cancer models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4663.

Soluble c-Met Levels Correlated With Tissue c-Met Protein Expression in Patients With Advanced Non–Small-Cell Lung Cancer

BackgroundImmunohistochemistry (IHC) and fluorescent in situ hybridization are reliable methods for identifying c-Met protein expression or c-Met gene amplification. However, each technique requires a high-quality tissue sample, which might not be available. The aim of the present study was to investigate the correlation between the soluble c-Met level and tissue c-Met protein expression and the relationship between these markers and patient prognosis. Materials and MethodsIn 198 patients with advanced non–small-cell lung cancer, tumor tissue c-Met expression was determined using IHC according to the H score criteria. Positivity was defined as ≥ 50% of cells with strong staining (IHC 3+). The concentration of c-Met protein in paired plasma samples was measured using a human soluble c-Met quantitative enzyme-linked immunosorbent assay kit, and the predictive value was determined using receiver operating characteristic curve analysis. ResultsOf the 198 patients, 140 (70.7%) had tissue c-Met− findings and 58 (29.3%) tissue c-Met+ findings. Receiver operating characteristic curve analysis showed 67.2% specificity and 65.0% sensitivity for predicting tissue c-Met positivity at a plasma c-Met cutoff of 766 ng/mL. The correlation between the soluble c-Met level and tissue c-Met protein expression was significant (Pearson's r = 0.309; P < .001). Patients with high soluble c-Met levels (> 766 ng/mL) had poorer overall survival than patients with low soluble c-Met levels (9.5 vs. 22.2 months; P < .001). Multivariate analyses demonstrated the same result (hazard ratio, 2.15; 95% confidence interval, 1.334-3.446; P = .002). ConclusionA significant correlation was found between the plasma soluble c-Met levels and tissue c-Met protein expression in patients with advanced non–small-cell lung cancer. A high level of soluble c-Met was associated with a poor prognosis.

Activated mutant forms of PIK3CA cooperate with RasV12 or c-Met to induce liver tumour formation in mice via AKT2/mTORC1 cascade.

Activating mutations of PIK3CA occur in various tumour types, including human hepatocellular carcinoma. The mechanisms whereby PIK3CA contributes to hepatocarcinogenesis remain poorly understood. PIK3CA mutants H1047R or E545K were hydrodynamically transfected, either alone or in combination with NRasV12 or c-Met genes, in the mouse liver. Overexpression of H1047R or E545K alone was able to induce AKT/mTOR signalling in the mouse liver, leading to hepatic steatosis. However, none of the mice developed liver tumours over long term. In contrast, H1047R or E545K cooperated with NRasV12 or c-Met to rapidly induce liver tumour formation in mice. At the molecular level, all the tumour nodules displayed activation of AKT/mTOR and Ras/MAPK cascades. Ablation of AKT2 significantly inhibited hepatic steatosis induced by H1047R or E545K and carcinogenesis induced by H1047R/c-Met or E545K/c-Met. Furthermore, tumourigenesis induced by H1047R/c-Met was abolished in conditional Raptor knockout mice. Both H1047R and E545K are able to activate the AKT/mTOR pathway. An intact AKT2/mTOR complex 1 cascade is required for tumourigenesis induced by H1047R/c-Met or E545K/c-Met in the liver.

Novel c-Met inhibitor suppresses the growth of c-Met-addicted gastric cancer cells.

Backgroundc-Met signaling has been implicated in oncogenesis especially in cells with c-met gene amplification. Since 20 % of gastric cancer patients show high level of c-Met expression, c-Met has been identified as a good candidate for targeted therapy in gastric cancer. Herein, we report our newly synthesized c-Met inhibitor by showing its efficacy both in vitro and in vivo.MethodsCompounds with both triazolopyrazine and pyridoxazine scaffolds were synthesized and tested using HTRF c-Met kinase assay. We performed cytotoxic assay, cellular phosphorylation assay, and cell cycle assay to investigate the cellular inhibitory mechanism of our compounds. We also conducted mouse xenograft assay to see efficacy in vivo.ResultsKRC-00509 and KRC-00715 were selected as excellent c-Met inhibitors through biochemical assay, and exhibited to be exclusively selective to c-Met by kinase panel assay. Cytotoxic assays using 18 gastric cancer cell lines showed our c-Met inhibitors suppressed specifically the growth of c-Met overexpressed cell lines, not that of c-Met low expressed cell lines, by inducing G1/S arrest. In c-met amplified cell lines, c-Met inhibitors reduced the downstream signals including Akt and Erk as well as c-Met activity. In vivo Hs746T xenograft assay showed KRC-00715 reduced the tumor size significantly.ConclusionsOur in vitro and in vivo data suggest KRC-00715 is a potent and highly selective c-Met inhibitor which may have therapeutic potential in gastric tumor with c-Met overexpression.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2058-y) contains supplementary material, which is available to authorized users.

Partial cloning of c-MET cDNA and its tissue distribution in Arabian camel (Camelus dromedarius)

The present study was, aimed to clone Hepatic growth factors receptor (c-Met). Arabian camels RT-PCR was conducted using liver tissue RNA and primers designed based on data from different animal species published in gene bank. The PCR product was sequenced and analysed using different bioinformatics programs. The results confirmed that the obtained sequence is related to c-Met gene family. The nucleotides sequence was deposited in the DDJB with accession number KC794957. Furthermore, the data showed base frequencies of A = 27.5%, C = 23.9%, G = 20.6% and T = 28.00%. Of the 600 nucleotides used for tree analyses, 454 were constant and 146 were variables. The neighbour-joining tree showed clustering of the species of family Camelidae with each other with strong bootstrapping (100 BP for MP and NJ methods). The deduced amino acids showed two non-synonymous substitutions discriminating C. dormedarius from other camelids; aspartic acid (D94) into histidine (H94) in other camelids at G281→C281 and glutamine (Q144) into histidine (H144) at A430 →C430. The results exhibited ubiquitous expression of c-Met mRNA in the tested tissues; kidney, liver, skeletal muscle, spleen, testis and heart. The obtained results are expected to be important for addressing the genetic diversity of the Afro-Arabian camel and clarifying the relationships among its available breeds.

Curcumin inhibited HGF-induced EMT and angiogenesis through regulating c-Met dependent PI3K/Akt/mTOR signaling pathways in lung cancer

The epithelial-mesenchymal transition (EMT) and angiogenesis have emerged as two pivotal events in cancer progression. Curcumin has been extensively studied in preclinical models and clinical trials of cancer prevention due to its favorable toxicity profile. However, the possible involvement of curcumin in the EMT and angiogenesis in lung cancer remains unclear. This study found that curcumin inhibited hepatocyte growth factor (HGF)-induced migration and EMT-related morphological changes in A549 and PC-9 cells. Moreover, pretreatment with curcumin blocked HGF-induced c-Met phosphorylation and downstream activation of Akt, mTOR, and S6. These effects mimicked that of c-Met inhibitor SU11274 or PI3 kinase inhibitor LY294002 or mTOR inhibitor rapamycin treatment. c-Met gene overexpression analysis further demonstrated that curcumin suppressed lung cancer cell EMT by inhibiting c-Met/Akt/mTOR signaling pathways. In human umbilical vein endothelial cells (HUVECs), we found that curcumin also significantly inhibited PI3K/Akt/mTOR signaling and induced apoptosis and reduced migration and tube formation of HGF-treated HUVEC. Finally, in the experimental mouse model, we showed that curcumin inhibited HGF-stimulated tumor growth and induced an increase in E-cadherin expression and a decrease in vimentin, CD34, and vascular endothelial growth factor (VEGF) expression. Collectively, these findings indicated that curcumin could inhibit HGF-promoted EMT and angiogenesis by targeting c-Met and blocking PI3K/Akt/mTOR pathways.

Small molecule inhibitor of c-Met (PHA665752) suppresses the growth of ovarian cancer cells and reverses cisplatin resistance.

c-Met as a tyrosine-kinase receptor plays a major role in tumorigenesis, invasion, and metastatic spread of human tumors, including ovarian cancer. Expressing high levels of c-Met proteins is often associated with resistance to chemotherapy and an adverse prognosis. In this study, we have determined the effect of PHA665752, a small molecule inhibitor of c-Met proteins, with and without cisplatin and the role of c-Met in several ovarian cancer cell lines having high c-Met expression. The methyl thiazolyl tetrazolium (MTT) assay was used to detect cell proliferation, and apoptosis was evaluated by flow cytometry. Western blotting was carried out to determine protein expression levels. Gene silencing was used to detect the influence of c-Met gene silence on the resistance to cisplatin. Compared to more sensitive ovarian cancer cell lines SKOV3 and 3AO, we found that the expression of c-Met was significantly increased in SKOV3(DDP), OVCAR3, and OV-90 ovarian cancer cell lines, which were resistant to cisplatin. Our data indicated that cisplatin sustained activated phosphor-Met in SKOV3(DDP), OVCAR3, and OV-90 cell lines. We also observed a significant transient activation of c-Met phosphorylation in SKOV3 and 3AO cells. Treatment with PHA665752 inhibited c-Met expression inhibited cell growth, induced apoptosis, and enhanced cisplatin-induced proliferation inhibition and apoptosis in c-Met over-expressed cell lines. In addition, blocking c-Met expression with small interfering RNA (siRNA) overcame the resistance of cancer cells to cisplatin. Thus, blocking c-Met expression presents a promising therapeutic approach for ovarian cancer.

Abstract PR03: Novel ceritinib resistance mechanisms: new resistant mutation, fibroblast growth factor receptor 3 overexpression and cMET amplification-mediated ceritinib resistance

Abstract Anaplastic lymphoma kinase (ALK) rearrangement, which was first identified in non-small cell lung cancer (NSCLC) in 2007, is observed in 3%-5% of non-small-cell lung cancer (NSCLC) patients. For the treatment of ALK-rearranged non-small-cell lung cancer (NSCLC) patient, crizotinib, cMET/ALK/ROS1-TKI was tested and has shown remarkable tumor shrinkage in clinical trials for the treatment of advanced ALK-rearranged NSCLC patients. However, these tumors inevitably develop resistance to crizotinib due to various secondary mutations, ALK fusion gene amplification, or bypass pathway activation mediated by other receptor tyrosine kinases. To overcome crizotinib resistance, multiple ALK-TKIs have been developed. Ceritinib, a next-generation ALK-TKI, showed great efficacy in crizotinib-refractory, ALK-rearranged NSCLC patients in a clinical trial. However, the emergence of resistance to ALK-TKI is a major limitation for the effective therapy. Although various secondary mutations or bypass pathway activation-mediated resistance have been identified, large part of the resistance mechanism is still unknown. In this study, we explored ceritinib-resistant mechanisms using ceritinib-resistant, echinoderm microtubule-associated protein-like 4-ALK-positive H3122 cells and ceritinib-resistant patient-derived cells. Genetic alteration was examined by sequencing of cancer related genes. Protein expression related to ceritinib was examined by receptor-tyrosine kinase (RTK) array, immunoblotting and IHC. To overcome the identified resistance, single or combination treatment of the kinase inhibitors was testes in vitro and in vivo. We identified three novel ceritinib resistance mechanisms: a resistance mutation (L1198F), fibroblast growth factor receptor 3 (FGFR3) activation, and cMET gene amplification. L1198F-mutated ALK was the most sensitive to crizotinib. Molecular dynamic structure simulation successfully predicted the affinity of ceritinib or crizotinib to wild type and L1198F-mutated ALK. The patient-derived cMET-amplified ceritinib-resistant cells were sensitive to crizotinib, and the FGFR3-upregulated, ceritinib-resistant H3122 cells were re-sensitized to ALK-TKIs by FGFR inhibitor co-treatment. Our study revealed multiple ceritinib resistance mechanisms and suggest that some of the ceritinib resistance can be overcome by crizotinib. Citation Format: Ryohei Katayama, Takuya Sakashita, Noriko Yanagitani, Kengo Takeuchi, Makoto Nishio, Naoya Fujita. Novel ceritinib resistance mechanisms: new resistant mutation, fibroblast growth factor receptor 3 overexpression and cMET amplification-mediated ceritinib resistance. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr PR03.