The mesenchymal-epithelial transition factor (MET) exon 14 skipping mutation is mainly caused by the loss of c-Cbl tyrosine binding site. This mutation could result in a decrease in the degradation rate of proteasome-mediated MET proteins, trigger continuous activation of downstream pathways, and ultimately lead to tumorigenesis. The incidence of MET exon 14 skipping mutation in patients with non-small cell lung cancer (NSCLC) is 0.9% to 4.0%. Patients with advanced NSCLC are recommended to test MET exon 14 skipping mutations who may benefit from MET inhibitors-targeted therapy. MET inhibitors have a high objective response rate and good safety profiles, which could prolong the survival of NSCLC patients with MET exon 14 skipping mutations. The Lung Cancer Specialty Committee of Chinese Elderly Health Care Association organized multidisciplinary experts to give suggestions on the important issues of clinical aspects for targeted therapy of MET exon 14 skipping mutation in NSCLC according to the clinical practice experiences and evidences based medicine. "Expert Consensus on Targeted Therapy of NSCLC with MET Exon 14 Skipping Mutation" is proposed, aiming to provide standardized guidances for the clinical practice of Chinese physicians.
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Humans ; Aged ; Carcinoma, Non-Small-Cell Lung/genetics* ; Lung Neoplasms/genetics* ; Consensus ; Proto-Oncogene Proteins c-met/genetics* ; Mutation ; Exons ; Protein Kinase Inhibitors/therapeutic use*

MET gene is a proto-oncogene, which encodes MET protein with tyrosine kinase activity. After binding to its ligand, hepatocyte growth factor, MET protein can induce MET dimerization and activate downstream signaling pathways, which plays a crucial role in tumor formation and metastasis. Savolitinib, as a specific tyrosine kinase inhibitor (TKI) targeting MET, selectively inhibits the phosphorylation of MET kinase with a significant inhibitory effect on tumors with MET abnormalities. Based on its significant efficacy shown in the registration studies, savolitinib was approved for marketing in China on June 22, 2021 for the treatment of advanced non-small cell lung cancer with MET 14 exon skipping mutations. In addition, many studies have shown that MET TKIs are equally effective in patients with advanced solid tumors with MET gene amplification or MET protein overexpression, and relevant registration clinical studies are ongoing. The most common adverse reactions during treatment with savolitinib include nausea, vomiting, peripheral edema, pyrexia, and hepatotoxicity. Based on two rounds of extensive nationwide investigations to guide clinicians, the consensus is compiled to use savolitinib rationally, prevent and treat various adverse reactions scientifically, and improve the clinical benefits and quality of life of patients. This consensus was prepared under the guidance of multidisciplinary experts, especially including the whole-process participation and valuable suggestions of experts in Traditional Chinese Medicine, thus reflecting the clinical treatment concept of integrated Chinese and western medicines.
Humans ; Carcinoma, Non-Small-Cell Lung/genetics* ; Lung Neoplasms/pathology* ; Consensus ; Quality of Life ; Proto-Oncogene Proteins c-met/genetics* ; Protein Kinase Inhibitors/adverse effects* ; Drug-Related Side Effects and Adverse Reactions ; Mutation

Humans ; Carcinoma, Non-Small-Cell Lung/genetics* ; China ; Consensus ; East Asian People ; Immunohistochemistry ; Lung Neoplasms/genetics* ; Proto-Oncogene Proteins c-met/genetics*

Mesenchymal-epithelial transition factor (MET) amplification is an important driver of resistance in epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC), and the combination of MET proto-oncogene (MET) and EGFR-tyrosine kinase inhibitors (TKIs) has shown promise in overcoming this molecularly defined acquired resistance. Emerging data also demonstrate MET amplification as a resistance driver to TKIs-treated anaplastic lymphoma kinase (ALK)-, RET-, and ROS1-fusion NSCLC. Here, we review the literature on recent research progress of MET amplification as a resistance driver to targeted therapy in oncogene-driven NSCLC and summarize the progress of clinical strategies to overcome the resistance mechanism.
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Carcinoma, Non-Small-Cell Lung/genetics* ; Drug Resistance, Neoplasm/genetics* ; ErbB Receptors/genetics* ; Humans ; Lung Neoplasms/pathology* ; Mutation ; Protein Kinase Inhibitors/therapeutic use* ; Protein-Tyrosine Kinases ; Proto-Oncogene Proteins/genetics* ; Proto-Oncogene Proteins c-met/genetics*

Targeted therapy is an important therapeutic method for advanced non-small cell lung cancer with driver gene alteration.However,resistance to targeted therapy will inevitably happen in clinical practice,which has become a major issue demanding prompt solution.Studies have demonstrated that bypass resistance mediated by the activation of hepatocyte growth factor(HGF)/mesenchymal-epithelial transition factor(MET)signaling pathway is a common cause of resistance to targeted therapy.Presently,relevant studies have accumulated rich experience in the specific mechanisms.To be brief,HGF/MET is an important target for overcoming the resistance to targeted therapy and promises to be a leading biomarker for judging and observing the occurrence of resistance.This paper introduces the recent studies concerning the effects and mechanisms of HGF/MET signaling pathway on resistance to targeted therapy.
Carcinoma, Non-Small-Cell Lung/genetics* ; Epithelial-Mesenchymal Transition ; Hepatocyte Growth Factor ; Humans ; Lung Neoplasms/genetics* ; Proto-Oncogene Proteins c-met/metabolism* ; Signal Transduction

Acrylamides ; Aniline Compounds ; Carcinoma, Non-Small-Cell Lung/genetics* ; Crizotinib/therapeutic use* ; Drug Resistance, Neoplasm/genetics* ; Erlotinib Hydrochloride/therapeutic use* ; Humans ; Lung Neoplasms/genetics* ; Mutation ; Protein Kinase Inhibitors/therapeutic use* ; Proto-Oncogene Proteins c-met/genetics*

Recently, targeted therapy has achieved great success in the treatment of non-small cell lung cancer (NSCLC) patients. Mesenchymal to epithelial transition factor (MET) is considered to be another important molecular target for NSCLC since epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK). Accumulating clinical trials and case reports have confirmed that MET inhibitors exhibited a potential prospect in treating patients with MET 14 exon skipping alterations, suggesting that MET 14 exon skipping mutation might be an effective biomarker for MET inhibitors, which remains to be confirmed by more clinical data. This review summarizes current research about the molecular mechanism, clinicopathological characterization, treatment strategies and drug resistance mechanisms of MET 14 exon skipping alterations in NSCLC.
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Carcinoma, Non-Small-Cell Lung ; drug therapy ; genetics ; Exons ; genetics ; Humans ; Lung Neoplasms ; drug therapy ; genetics ; Molecular Targeted Therapy ; Mutation ; Proto-Oncogene Proteins c-met ; genetics

Humans ; Proto-Oncogene Proteins c-met ; genetics ; metabolism ; Stomach Neoplasms ; genetics ; metabolism

This research aims to construct a lentiviral expression vector carrying the extracelluar domain (ED) of human hepatocyte growth factor receptor (C-Met), and to express it in transfected 293T cells. The extracellular domain of C-Met was amplified by RT-PCR, ligated with lentiviral expression vector p RRL-CMV-ED, and then expressed in 293T cell line. The expressed protein was purified and identified by RT-PCR and Western blot. The enzyme digestion and sequence analysis showed that the lentiviral expression vector p RRL-CMV-ED was constructed correctly. The size of amplified genes was about 2 700 bp. The purified protein with Ni-affinity column was about 105 kD analyzed by SDS-PAGE. The Western blot and ELISA results showed that the expressed protein which could bind to HGF specifically was the extracelluar domain of human hepatocyte growth factor receptor. This research may lay a foundation for further study of anti-C-MET monoclonal antibody and neutralizing antibody.
Genetic Vectors ; HEK293 Cells ; Humans ; Lentivirus ; Proto-Oncogene Proteins c-met ; genetics ; metabolism ; Transfection

OBJECTIVETo observe the inhibition of NK4 protein in the proliferation of human Raji lymphoma xenografts in nude mice, and to explore its molecular mechanism.

METHODSModels of human Raji lymphoma xenograft transfected with HGF gene were established by subcutaneous inoculation in nude mice. After establishment of the models, the mice received continuous NK4 protein via tail vein for 4 weeks, and the weight and tumor growth were monitored every week. After 8 weeks, the expression of HGF mRNA and c-Met mRNA of tumor tissues was measured by real-time fluorescent quantitation PCR. The apoptotic index (AI) and microvessel density (MVD) were evaluated by terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) and immunohistochemistry, respectively.

RESULTSThe models of human Raji lymphoma xenograft were successfully established. Although the animal weights of all groups declined, especially in the groups with NK4 protein injection, there was no statistical significance (P > 0.05). The tumor volume in HGF gene transfected group was larger than those of the control groups (P < 0.01), and there was no statistical significance among the control groups (P > 0.05). However, the tumor volume of the NK4 protein injection group decreased significantly (P < 0.01). Expression of HGF mRNA and c-Met mRNA in HGF gene transfected group increased significantly after injection of NK4 protein (P < 0.01). AI in HGF gene transfected group (33.5% ± 12.3%) was significantly lower than that of control groups (89.1% ± 22.3% vs. 81.9% ± 27.0%, P < 0.05), but became significantly higher (119.1% ± 18.9%) after NK4 protein injection (P < 0.01). MVD in HGF gene transfected group (28.5 ± 2.0) was higher than that of control groups (12.2 ± 1.4, 13.8 ± 1.3, P < 0.01), although declined (15.5 ± 2.5) after NK4 protein injection (P < 0.01).

CONCLUSIONSNK4 protein suppresses significantly the growth of human Raji lymphoma xenografts transfected with HGF gene. The pathogenesis may be involved in promoting tumor cell apoptosis and restraining tumor angiogenesis through competitive interrupting HGF/Met signal pathway.

Animals ; Apoptosis ; Hepatocyte Growth Factor ; genetics ; metabolism ; Heterografts ; Humans ; Lymphoma ; genetics ; metabolism ; therapy ; Mice ; Mice, Nude ; Microvessels ; pathology ; Neovascularization, Pathologic ; Proto-Oncogene Proteins c-met ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Signal Transduction ; T-Box Domain Proteins ; administration & dosage ; Transfection ; Transplantation, Heterologous