Lack of association of C-Met-N375S sequence variant with lung cancer susceptibility and prognosis

Therapeutic advances of targeting receptor tyrosine kinases in cancer

Receptor tyrosine kinases (RTKs), a category of transmembrane receptors, have gained significant clinical attention in oncology due to their central role in cancer pathogenesis. Genetic alterations, including mutations, amplifications, and overexpression of certain RTKs, are critical in creating environments conducive to tumor development. Following their discovery, extensive research has revealed how RTK dysregulation contributes to oncogenesis, with many cancer subtypes showing dependency on aberrant RTK signaling for their proliferation, survival and progression. These findings paved the way for targeted therapies that aim to inhibit crucial biological pathways in cancer. As a result, RTKs have emerged as primary targets in anticancer therapeutic development. Over the past two decades, this has led to the synthesis and clinical validation of numerous small molecule tyrosine kinase inhibitors (TKIs), now effectively utilized in treating various cancer types. In this manuscript we aim to provide a comprehensive understanding of the RTKs in the context of cancer. We explored the various alterations and overexpression of specific receptors across different malignancies, with special attention dedicated to the examination of current RTK inhibitors, highlighting their role as potential targeted therapies. By integrating the latest research findings and clinical evidence, we seek to elucidate the pivotal role of RTKs in cancer biology and the therapeutic efficacy of RTK inhibition with promising treatment outcomes.

MET Mutation Is a Potential Therapeutic Target for Advanced Endometrial Cancer

Simple Summary

Endometrial cancer is the most common gynecological cancer in developed countries. At initial diagnosis, extra-uterine spread is observed in about 25% of patients. Chemotherapy is the suggested mode of treatment for patients with extra-uterine metastasis; however, the 5-year overall survival rate of these patients remains poor. The development of new therapeutic strategies to improve the poor clinical outcome of patients with advanced endometrial cancer is still in great demand. In this study, we aim to understand the genomic landscape of advanced endometrial cancer and identify new therapeutic targets. Integrated genomic, pathological, and clinical data are analyzed to identify the survival-associated genomic alterations. In addition, the impacts of the genomic alterations are examined in silico, in vitro, and in vivo. The results of this study may aid in developing biomarker-guided treatments for patients with advanced endometrial cancer.

Abstract

An optimal therapeutic regimen for endometrial cancer with extra-uterine metastasis is unavailable. This study aims to improve our understanding of the genomic landscape of advanced endometrial cancer and identify potential therapeutic targets. The clinical and genomic profiles of 81 patients with stage III or IV endometrial cancer were integrated. To identify genomic aberrations associated with clinical outcomes, Cox proportional hazard regression was used. The impacts of the genomic aberrations were validated in vitro and in vivo. The mutation status of MET, U2AF1, BCL9, PPP2R1A, IDH2, CBL, BTK, and CHEK2 were positively correlated with poor clinical outcomes. MET mutations occurred in 30% of the patients who presented with poor overall survival (hazard ratio, 2.606; 95% confidence interval, 1.167~5.819; adjusted p-value, 0.067). Concurrent MET and KRAS mutations presented with the worst outcomes. MET mutations in hepatocyte growth factor (HGF)-binding (58.1%) or kinase (16.2%) domains resulted in differential HGF-induced c-MET phosphorylation. Different types of MET mutations differentially affected tumor growth and displayed different sensitivities to cisplatin and tyrosine kinase inhibitors. MET N375S mutation is a germline variant that causes chemoresistance to cisplatin, with a high incidence in Eastern Asia. This study highlights the ethnic differences in the biology of the disease, which can influence treatment recommendations and the genome-guided clinical trials of advanced endometrial cancer.

A narrative review of MET inhibitors in non-small cell lung cancer with MET exon 14 skipping mutations

Treatment of advanced non-small cell lung cancer (NSCLC) has radically improved in the last years due to development and clinical approval of highly effective agents including immune checkpoint inhibitors (ICIs) and oncogene-directed therapies. Molecular profiling of lung cancer samples for activated oncogenes, including epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1) and BRAF, is routinely performed to select the most appropriate up-front treatment. However, the identification of new therapeutic targets remains a high priority. Recently, MET exon 14 skipping mutations have emerged as novel actionable oncogenic alterations in NSCLC, sensitive to MET inhibition. In this review we discuss: (I) MET gene and MET receptor structure and signaling pathway; (II) MET exon 14 alterations; (III) current data on MET inhibitors, mainly focusing on selective MET tyrosine kinase inhibitors (TKIs), in the treatment of NSCLC with MET exon 14 skipping mutations. We identified the references for this review through a literature search of papers about MET, MET exon 14 skipping mutations, and MET inhibitors, published up to September 2020, by using PubMed, Scopus and Web of Science databases. We also searched on websites of main international cancer congresses (ASCO, ESMO, IASLC) for ongoing studies presented as abstracts. MET exon 14 skipping mutations have been associated with clinical activity of selective MET inhibitors, including capmatinib, that has recently received approval by FDA for clinical use in this subgroup of NSCLC patients. A large number of trials are testing MET inhibitors, also in combinatorial therapeutic strategies, in MET exon 14-altered NSCLC. Results from these trials are eagerly awaited to definitively establish the role and setting for use of these agents in NSCLC patients.

A common MET polymorphism harnesses HER2 signaling to drive aggressive squamous cell carcinoma

c-MET receptors are activated in cancers through genomic events like tyrosine kinase domain mutations, juxtamembrane splicing mutation and amplified copy numbers, which can be inhibited by c-MET small molecule inhibitors. Here, we discover that the most common polymorphism known to affect MET gene (N375S), involving the semaphorin domain, confers exquisite binding affinity for HER2 and enables MET^N375S to interact with HER2 in a ligand-independent fashion. The resultant MET^N375S/HER2 dimer transduces potent proliferative, pro-invasive and pro-metastatic cues through the HER2 signaling axis to drive aggressive squamous cell carcinomas of the head and neck (HNSCC) and lung (LUSC), and is associated with poor prognosis. Accordingly, HER2 blockers, but not c-MET inhibitors, are paradoxically effective at restraining in vivo and in vitro models expressing MET^N375S. These results establish MET^N375S as a biologically distinct and clinically actionable molecular subset of SCCs that are uniquely amenable to HER2 blocking therapies.

The MET receptor is frequently activated in cancer. Here, the authors show that in head and neck and lung squamous carcinoma, a polymorphic MET variant enhances binding to HER2, resulting in activation of HER2 signalling and progression of the cancers.

Luirink R, P. Geerke D, Op de Beeck K, Hermans C, Tiseo M, Van Schil P, Lardon F, Germonpré P, Rolfo C, Giovannetti E, J. Peters G, Pauwels P. The Role of c-Met as a Biomarker and Player in Innate and Acquired Resistance in Non-Small-Cell Lung Cancer: Two New Mutations Warrant Further Studies

The c-Met receptor is a therapeutically actionable target in non-small-cell lung cancer (NSCLC), with one approved drug and several agents in development. Most suitable biomarkers for patient selection include c-Met amplification and exon-14 skipping. Our retrospective study focused on the frequency of different c-Met aberrations (overexpression, amplification and mutations) in 153 primary, therapy-naïve resection samples and their paired metastases, from Biobank@UZA. Furthermore, we determined the correlation of c-Met expression with clinicopathological factors, Epidermal Growth Factor Receptor (EGFR)-status and TP53 mutations. Our results showed that c-Met expression levels in primary tumors were comparable to their respective metastases. Five different mutations were detected by deep sequencing: three (E168D, S203T, N375S) previously described and two never reported (I333T, G783E). I333T, a new mutation in the Sema(phorin) domain of c-Met, might influence the binding of antibodies targeting the HGF-binding domain, potentially causing innate resistance. E168D and S203T mutations showed a trend towards a correlation with high c-Met expression (p = 0.058). We found a significant correlation between c-MET expression, EGFR expression (p = 0.010) and EGFR mutations (p = 0.013), as well as a trend (p = 0.057) with regards to TP53 mutant activity. In conclusion this study demonstrated a strong correlation between EGFR mutations, TP53 and c-Met expression in therapy-naïve primary resection samples. Moreover, we found two new c-Met mutations that warrant further studies.

Proteolytic cleavages of MET: the divide-and-conquer strategy of a receptor tyrosine kinase

Membrane-anchored full-length MET stimulated by its ligand HGF/SF induces various biological responses, including survival, growth, and invasion. This panel of responses, referred to invasive growth, is required for embryogenesis and tissue regeneration in adults. On the contrary, MET deregulation is associated with tumorigenesis in many kinds of cancer. In addition to its well-documented ligand-stimulated downstream signaling, the receptor can be cleaved by proteases such as secretases, caspases, and calpains. These cleavages are involved either in MET receptor inactivation or, more interestingly, in generating active fragments that can modify cell fate. For instance, MET fragments can promote cell death or invasion. Given a large number of proteases capable of cleaving MET, this receptor appears as a prototype of proteolytic-cleavage-regulated receptor tyrosine kinase. In this review, we describe and discuss the mechanisms and consequences, both physiological and pathological, of MET proteolytic cleavages.

The multiple paths towards MET receptor addiction in cancer

Targeted therapies against receptor tyrosine kinases (RTKs) are currently used with success on a small proportion of patients displaying clear oncogene activation. Lung cancers with a mutated EGFR provide a good illustration. The efficacy of targeted treatments relies on oncogene addiction, a situation in which the growth or survival of the cancer cells depends on a single deregulated oncogene. MET, a member of the RTK family, is a promising target because it displays many deregulations in a broad panel of cancers. Although clinical trials having evaluated MET inhibitors in large populations have yielded disappointing results, many recent case reports suggest that MET inhibition may be effective in a subset of patients with unambiguous MET activation and thus, most probably, oncogene addiction. Interestingly, preclinical studies have revealed a particularity of MET addiction: it can arise through several mechanisms, and the mechanism involved can differ according to the cancer type. The present review describes the different mechanisms of MET addiction and their consequences for diagnosis and therapeutic strategies. Although in each cancer type MET addiction affects a restricted number of patients, pooling of these patients across all cancer types yields a targetable population liable to benefit from addiction-targeting therapies.

MET receptor variant R970C favors calpain-dependent generation of a fragment promoting epithelial cell scattering

The receptor tyrosine kinase MET and its ligand, the hepatocyte growth factor, are essential to embryonic development, whereas deregulation of MET signaling is associated with tumorigenesis leading to various cancers, including lung carcinoma. Mutations in the MET kinase domain lead to constitutive kinase activity and are associated with tumorigenesis. In lung cancer, however, some mutations are found in the juxtamembrane domain, and their functional consequences are unknown. Because the juxtamembrane domain of MET is targeted by several proteolytic cleavages, involved in its degradation during cell death or under steady-state conditions, we evaluated the influence of these mutations on the MET proteolytic cleavages. In stably transfected epithelial cells expressing MET, the juxtamembrane mutations R970C, P991S, and T992I were found not to modify the known caspase or presenilin-dependent regulated intramembrane proteolysis. Yet when overexpressed, the R970C variant caused generation of an as yet undescribed 45-kDa fragment (p45 MET). This fragment was found in the confluent lung cancer cell line NCI-H1437 carrying the R970C mutation and at a lesser extent in cell lines expressing WT MET, suggesting that R970C mutation favors this cleavage. Generation of p45 MET required the activity of the calpain proteases, confirming the involvement of proteolysis. Ectopic expression of reconstituted p45 MET in epithelial cell lines favored cell scattering and invasion indicating active role of this fragment in HGF/SF induced responses. Hence, although the juxtamembrane mutations of MET do not affect its known proteolytic cleavages, the R970C MET variant favors calpain dependent proteolytic cleavage in lung cancer cells.

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

BACKGROUND

Immunohistochemistry (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 METHODS

In 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.

RESULTS

Of 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).

CONCLUSION

A 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.

Establishment and application of a multiplex genetic mutation-detection method of lung cancer based on MassARRAY platform

Objective: This study aims to establish a method for highly parallel multiplexed detection of genetic mutations in Chinese lung cancer samples through Agena iPLEX chemistry and matrix-assisted laser desorption ionization time-of-flight analysis on MassARRAY mass spectrometry platform. Methods: We reviewed the related literature and data on lung cancer treatments. We also identified 99 mutation hot spots in 13 target genes closely related to the pathogenesis, drug resistance, and metastasis of lung cancer. A total of 297 primers, composed of 99 paired forward and reverse amplification primers and 99 matched extension primers, were designed using Assay Design software. The detection method was established by analyzing eight cell lines and six lung cancer specimens. The proposed method was then validated through comparisons by using a LungCarta^TM kit. The sensitivity and specificity of the proposed method were evaluated by directly sequencing EGFR and KRAS genes in 100 lung cancer cases. Results: The proposed method was able to detect multiplex genetic mutations in lung cancer cell lines. This finding was consistent with the observations on previously reported mutations. The proposed method can also detect such mutations in clinical lung cancer specimens. This result was consistent with the observations with LungCarta^TM kit. However, an FGFR2 mutation was detected only through the proposed method. The measured sensitivity and specificity were 100% and 96.3%, respectively. Conclusions: The proposed MassARRAY technology-based multiplex method can detect genetic mutations in Chinese lung cancer patients. Therefore, the proposed method can be applied to detect mutations in other cancer tissues.

[Mechanism of c-MET in Non-small Cell Lung Cancer and Its Treatment and Testing]

Hepatocyte growth factor/c-MET (HGF/c-MET) signaling pathway can be abnormal activated by many mechanisms such as c-MET mutation, amplification and the overexpression of HGF, and it plays an important role in the development of non-small cell lung cancer (NSCLC), as well as in the tolerance of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) in NSCLC. Therefore, c-MET is a new molecular target for the therapy of NSCLC since EGFR and ALK. At present, although the c-MET inhibitors have shown a potential prospect in some clinical trials, its assessment of safety and effectiveness in clinical applications, and the choice of testing methods and standards still need a further discussion. In this paper, we summarized the mechanism of c-MET in NSCLC, as well as its treatment prospect and selection of testing methods.

MET aberrations and c-MET inhibitors in patients with gastric and esophageal cancers in a phase I unit

We sought to investigate the demographics and tumor-associated features in patients with gastroesophageal (GE) malignancies referred to our Phase I Program who had formalin-fixed, paraffin-embedded tissue from archival or new biopsies tested for MET mutation and/or amplification. MET amplification was found in 5 of 76 (6.6%) patients (3/34 [8.8%] esophageal, 2/26 [7.7%] gastric and none in 22 gastroesophageal junction cancers). The only MET mutation detected in 3 of 41 (7.3%) patients was N375S. No demographic and histologic characteristics were associated with specific MET abnormalities. Median overall survival was 3 and 5 months for patients with and without a MET alteration, respectively (hazard ratio [HR] = 2.1; 95% CI, 0.8 to 5.5; P=.14). Sixteen of 81 (20%) patients were enrolled in a c-MET inhibitor trial. Best responses were stable disease in 3 patients (19%), including a patient with esophageal adenocarcinoma that remained on the trial for 9.9 months (wild-type for MET abnormality). All tumors with MET abnormality (n=3) progressed on a c-MET inhibitor in fewer than 2 months. In conclusion, MET abnormalities can be found in a small group of patients with GE adenocarcinoma and further studies are necessary to better characterize the prognostic and predictive impact of MET alterations.

Targeting the MET pathway for potential treatment of NSCLC

INTRODUCTION

The mesenchymal-epithelial transition (MET) protein is the only known receptor for hepatocyte growth factor and has recently been identified as a novel promising target in several human cancers, including NSCLC. Activation of the MET signaling pathway can occur via different mechanisms. A number of compounds targeting MET have been evaluated in clinical trials, and recent clinical data have begun to afford some insight into the tumor types and patient populations that might benefit from treatment with MET pathway inhibitors.

AREAS COVERED

We review recent publications and information disclosed at public conferences and summarize the epidemiology of dysregulation of MET signaling, and the associations thereof with other driver genes and therapeutic inhibitors useful to treat NSCLC.

EXPERT OPINION

The MET pathway is emerging as a target for advanced NSCLC that is either resistant to EGFR tyrosine kinase inhibitors or that arises de novo. MET inhibitors currently being evaluated in clinical trials have yielded compelling evidence of clinical activities when used to treat various solid tumors, especially NSCLC. Remaining challenges are the identification of patient populations who might benefit from the use of MET inhibitors, and the most effective diagnostic methods for such patients.

Tongue carcinoma infrequently harbor common actionable genetic alterations

BACKGROUND

Oral tongue squamous cell carcinomas (TSCC) are a unique subset of head and neck cancers with a distinct demographic profile, where up to half of the cases are never smokers. A small proportion of patients with OSCC are known to respond to EGFR TKI. We used a high-sensitivity mass spectrometry-based mutation profiling platform to determine the EGFR mutation status, as well as other actionable alterations in a series of Asian TSCC.

METHODS

66 TSCC patients treated between 1998-2009 with complete clinico-pathologic data were included in this study. Somatic mutation profiling was performed using Sequenom LungCarta v1.0, and correlated with clinical parameters.

RESULTS

Mutations were identified in 20/66(30.3%) of samples and involved TP53, STK11, MET, PIK3CA, BRAF and NRF2. No activating EGFR mutations or KRAS mutations were discovered in our series, where just over a third were never smokers. The most common mutations were in p53 (10.6%; n = 7) and MET (10.6%, n = 11) followed by STK11 (9.1%, n = 6) and PIK3CA (4.5%, n = 3). BRAF and NRF2 mutations, which are novel in TSCC, were demonstrated in one sample each. There was no significant correlation between overall mutation status and smoking history (p = 0.967) or age (p = 0.360). Positive MET alteration was associated with poorer loco-regional recurrence free survival (LRFS) of 11 months [vs 90 months in MET-negative group (p = 0.008)]. None of the other mutations were significantly correlated with LRFS or overall survival. Four of these tumors were propagated as immortalized cell lines and demonstrated the same mutations as the original tumor.

CONCLUSIONS

Using the Sequenom multiplexed LungCarta panel, we identified mutations in 6 genes, TP53, STK11, MET, PIK3CA, BRAF and NRF2, with the notable absence of EGFR and HER2 mutations in our series of Asian OSCC. Primary cell line models recapitulated the mutation profiles of the original primary tumours and provide an invaluable resource for experimental cancer therapeutics.

The Met receptor tyrosine kinase: a key player in oncogenesis and drug resistance

The Met receptor tyrosine kinase (RTK) is an attractive oncology therapeutic target. Met and its ligand, HGF, play a central role in signaling pathways that are exploited during the oncogenic process, including regulation of cell proliferation, invasion, angiogenesis, and cancer stem cell regulation. Elevated Met and HGF as well as numerous Met genetic alterations have been reported in human cancers and correlate with poor outcome. Alterations of pathways that regulate Met, such as the ubiquitin ligase c-Cbl are also likely to activate Met in the oncogenic setting. Moreover, interactive crosstalk between Met and other receptors such as EGFR, HER2 and VEGFR, underlies a key role for Met in resistance to other RTK-targeted therapies. A large body of preclinical and clinical data exists that supports the use of either antibodies or small molecule inhibitors that target Met or HGF as oncology therapeutics. The prognostic potential of Met expression has been suggested from studies in numerous cancers including lung, renal, liver, head and neck, stomach, and breast. Clinical trials using Met inhibitors indicate that the level of Met expression is a determinant of trial outcome, a finding that is actively under investigation in multiple clinical scenarios. Research in Met prognostics and predictors of drug response is now shifting toward more sophisticated methodologies suitable for development as validated and effective biomarkers that can be partnered with therapeutics to improve patient survival.