The Prognostic Role of MET Protein Expression Among Surgically Resected Non-small Cell Lung Cancer Patients: A Meta-Analysis

Telomerase deficiency and dysfunctional telomeres in the lung tumor microenvironment impair tumor progression in NSCLC mouse models and patient-derived xenografts

Non-small cell lung cancer (NSCLC) is a leading cause of cancer death. Tumor progression depends on interactions of cancer cells with the tumor microenvironment. Here, we find increased copy number and mRNA expression of the catalytic subunit of telomerase, TERT, in tumors from NSCLC patients, contributing to a lower survival. Moreover, TERT expression in NSCLC patients from the TCGA cohort is mainly associated to the reduced infiltration of CD8⁺ T lymphocytes, as well as to increased infiltration of myeloid-derived suppressor cells (MDSCs). We also show that TERT deficiency and dysfunctional telomeres induced by 6-thio-dG treatment in mice reduced lung tumor implantation and vascularization, increased DNA damage response, cell cycle arrest and apoptosis, as well as reduced proliferation, inflammation, lung tumor immunosupression and invasion upon induction of a Lewis lung carcinoma (LLC). Furthermore, 6-thio-dG-treated human NSCLC xenografts exhibited increased telomere damage, cell cycle arrest and apoptosis, as well as reduced proliferation, resulting in a reduced tumor growth. Our results show that targeting telomeres might be an effective therapeutic strategy in NSCLC.

Engineering c-Met-CAR NK-92 cells as a promising therapeutic candidate for lung adenocarcinoma

Mesenchymal-epithelial transition factor (C-Met) has been acknowledged as a significant therapeutic target for treating lung adenocarcinoma (LUAD). However, the potential application of chimeric antigen receptors (CAR)-modified natural killer (NK) cells targeting c-Met in LUAD is rarely explored. In this study, bioinformatic databases were searched and a tissue microarray (TMA) was enrolled to investigate expression status and prognostic role of c-Met in LUAD. Then, four types of c-Met-CAR structures were designed and prepared. The engineering CAR-NK cells containing c-Met-CARs were transfected, verified and characterized. The tumor-inhibitory role of c-Met-CAR-NK cells was finally evaluated in vitro and in vivo. The results demonstrated that c-Met expression elevated and confirmed that high c-Met expression was significantly associated with unfavorable prognosis in LUAD. Then, C-Met-CAR-NK cells were successfully constructed and DAP10 designed in CAR structure was a favorable stimulator for NK cell activation. CCN4 containing DAP10 co-stimulator exhibited the strongest cytotoxicity compared with other CAR-NK cells. Furthermore, CCN4 cells also exerted the prominent tumor-inhibitory effect on xenograft tumor growth. Collectively, this study suggests that DAP10 is a potent stimulator in CAR structure for NK cell activation, and CCN4-based immunotherapy may represent a promising strategy for the treatment of c-Met-positive LUAD.

Management and Treatment of Non-small Cell Lung Cancer with MET Alteration and Mechanisms of Resistance

OPINION STATEMENT

MET-driven tumors are a heterogenous group of non-small cell lung cancers (NSCLC) with activating mutations. Pathologic activation of MET can be achieved with increased number of gene copies overexpression, or decreased protein degradation through several mechanisms, including mutations, amplifications, or fusions. Besides its role as primary driver, MET activation might also mediate resistance to kinase inhibitors in NSCLC with various other actionable alterations. While checkpoint inhibitors have modest efficacy in MET-driven tumors, several approaches of targeted blockade are available. Among them the most promising are small tyrosine kinase inhibitors, antibody-drug conjugates, and bispecific antibodies. Unfortunately, resistance is virtually inevitable. Resistance to small kinase inhibitors might be mediated by kinase domain mutations or activation of shunting cascades. Various resistance mechanisms might be present in one patient, making it overcoming an unresolved problem.

KRAS and MET in non-small-cell lung cancer: two of the new kids on the 'drivers' block

Non-small-cell lung cancer (NSCLC) is a heterogeneous disease, and therapeutic management has advanced to identify various critical oncogenic mutations that promote lung cancer tumorigenesis. Subsequent studies have developed targeted therapies against these oncogenes in the hope of personalized treatment based on the tumor's molecular genomics. This review presents a comprehensive review of the biology, new therapeutic interventions, and resistance patterns of two well-defined subgroups, tumors with KRAS and MET alterations. We also discuss the status of molecular testing practices for these two key oncogenic drivers, considering the progressive introduction of next-generation sequencing (NGS) and RNA sequencing in regular clinical practice.