Functional expression and mutations of c-Met and its therapeutic inhibition with SU11274 and small interfering RNA in non-small cell lung cancer

Oncogenic mechanism-based pharmaceutical validation of therapeutics targeting MET receptor tyrosine kinase

Aberrant expression and/or activation of the MET receptor tyrosine kinase is characterized by genomic recombination, gene amplification, activating mutation, alternative exon-splicing, increased transcription, and their different combinations. These dysregulations serve as oncogenic determinants contributing to cancerous initiation, progression, malignancy, and stemness. Moreover, integration of the MET pathway into the cellular signaling network as an addiction mechanism for survival has made this receptor an attractive pharmaceutical target for oncological intervention. For the last 20 years, MET-targeting small-molecule kinase inhibitors (SMKIs), conventional therapeutic monoclonal antibodies (TMABs), and antibody-based biotherapeutics such as bispecific antibodies, antibody–drug conjugates (ADC), and dual-targeting ADCs have been under intensive investigation. Outcomes from preclinical studies and clinical trials are mixed with certain successes but also various setbacks. Due to the complex nature of MET dysregulation with multiple facets and underlying mechanisms, mechanism-based validation of MET-targeting therapeutics is crucial for the selection and validation of lead candidates for clinical trials. In this review, we discuss the importance of various types of mechanism-based pharmaceutical models in evaluation of different types of MET-targeting therapeutics. The advantages and disadvantages of these mechanism-based strategies for SMKIs, conventional TMABs, and antibody-based biotherapeutics are analyzed. The demand for establishing new strategies suitable for validating novel biotherapeutics is also discussed. The information summarized should provide a pharmaceutical guideline for selection and validation of MET-targeting therapeutics for clinical application in the future.

Novel Therapies for Metastatic Non-Small Cell Lung Cancer with MET Exon 14 Alterations: A Spotlight on Capmatinib

MET exon 14 (METex14) alterations are now an established therapeutically tractable target in non-small cell lung cancer (NSCLC). Recently reported trials of several MET tyrosine kinase inhibitors (TKI) in this patient population have demonstrated promising efficacy data in both the treatment naïve and pre-treated settings and have led to regulatory approvals. This review will focus on practical diagnostic considerations for METex14 alterations, the trial evidence for capmatinib in this molecular subset including dosing and toxicity management, and the future therapeutic landscape of METex14 altered NSCLC.

Uncommon targets in non-small cell lung cancer: Everyone wants a slice of cake

Target therapies completely changed the clinical approach in EGFR mutated and ALK rearranged non-small cell lung cancer, ensuring these patients exceptional outcomes with a better toxicity profile compared to conventional chemotherapy. In recent years, beyond EGFR and ALK alterations, new data are emerging about less common alterations, new drugs have been already approved and others agents have been recently investigated or are currently under investigation. In this review we will discuss some uncommon alterations in non-small cell lung cancer such as ROS1, BRAF, RET, HER2, NTRK, MET and other targets that are in an early evaluation phase. We will summarize the characteristics of patients harboring these alterations, the already approved or under investigation therapies and the related resistance mechanisms.

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.

Current and future treatment options for MET exon 14 skipping alterations in non-small cell lung cancer

It has been over three decades since the hepatocyte growth factor (HGF) ligand and its receptor MET proto-oncogene (MET) pathway was established as promoting cancer growth and metastasis. MET exon 14 skipping (METex14) alterations occur in 3-4% of all non-small cell lung cancer (NSCLC) patients, typically in elderly patients (older than 70 years), and result in constitutive activation of the MET receptor by altering a region required for receptor degradation. Multi-kinase inhibitor of MET, such as crizotinib, and more recently selective MET inhibitors, such as capmatinib and tepotinib, have demonstrated clinical efficacy and safety in METex14 NSCLC patients in clinical trials. These results have led to the approval of MET inhibitors by regulatory agencies across the globe. The success also fueled the excitement of further development of therapeutic strategies to target METex14 in lung cancers. This article provides an overview of the clinical development program targeting METex14 in NSCLC, including small molecular tyrosine kinase inhibitors and anti-MET antibodies. Furthermore, combination therapy immune checkpoint inhibitors or other targeted therapies are also under development in various patient populations, with acquired resistance immune or targeted therapy. Clinical trials in different development stages are ongoing and more drugs targeted to c-MET will be available for NSCLC patients with METex14 skipping mutations in the future.

The Clinical Impact of Capmatinib in the Treatment of Advanced Non-Small Cell Lung Cancer with MET Exon 14 Skipping Mutation or Gene Amplification

Purpose

Capmatinib, an oral MET kinase inhibitor, has demonstrated its efficacy against non–small cell lung cancer (NSCLC) with MET dysregulation. We investigated its clinical impact in advanced NSCLC with MET exon 14 skipping mutation (METex14) or gene amplification.

Materials and Methods

Patients who participated in the screening of a phase II study of capmatinib for advanced NSCLC were enrolled in this study. MET gene copy number (GCN), protein expression, and METex14 were analyzed and the patients’ clinical outcome were retrospectively reviewed.

Results

A total of 72 patients were included in this analysis (group A: GCN ≥ 10 or METex14, n=14; group B: others, n=58). Among them, 13 patients were treated with capmatinib (group A, n=8; group B, n=5), and the overall response rate was 50% for group A, and 0% for group B. In all patients, the median overall survival (OS) was 20.2 months (95% confidence interval [CI], 6.9 to not applicable [NA]) for group A, and 11.3 months (95% CI, 8.2 to 20.3) for group B (p=0.457). However, within group A, median OS was 21.5 months (95% CI, 20.8 to NA) for capmatinib-treated, and 7.5 months (95% CI, 3.2 to NA) for capmatinib-untreated patients (p=0.025). Among all capmatinib-untreated patients (n=59), group A showed a trend towards worse OS to group B (median OS, 7.5 months vs. 11.3 months; p=0.123).

Conclusion

Our data suggest that capmatinib is a new compelling treatment for NSCLC with MET GCN ≥ 10 or METex14 based on the improved survival within these patients.

Simple Synthesis of a Heterocyclophane Exhibiting Anti-c-Met Activity by Acting as a Hatch Blocking Access to the Active Site*

A simple approach to the synthesis of heterocyclophane consisting of two 4,4'-bithiazoles has been developed in mild conditions. The heterocyclophane with two short chains was conveniently prepared by Hantzsch thiazoles synthesis using the reaction of 3-tert-butoxycarbonyl-3-azapentanethiocarboxamide with 1,4-dibromobutane-2,3-dione in methanol under reflux for only 15 min. Amino groups at the linkers of this heterocyclophane can be functionalized to give acylated and carbamate derivatives. Their properties as protein kinase inhibitors were investigated, and one of the heterocyclophanes exhibited specific anti-activity for c-mesenchymal epithelial transition factor (IC50 =603 nm), among seven types of protein kinases investigated. The computational site identification by ligand competitive saturation method was used to determine why the one heterocyclophane exhibited strong anti-activity for c-mesenchymal epithelial transition factor.

Narrative review: mesenchymal-epithelial transition inhibitors-meeting their target

Genetic alterations in mesenchymal-epithelial transition (MET) are commonly found in solid tumors, especially in non-small cell lung cancer (NSCLC). However, agents targeting MET have not progressed until recently. Advancements in our understanding of the role of various MET aberrations in carcinogenesis have allowed MET-directed therapy to find its way to clinic use. Of all MET alterations, MET exon 14 skipping (METex14 skip⁺ or MET^∆14), stands out as a true oncogenic driver. Recently, MET tyrosine kinase inhibitors (TKI) targeting METex14 skipping were able to demonstrate significant improvement in clinical outcomes including response rate and progression free survival. Of these, capmatinib was granted accelerated approval by the FDA in May 2020 for patients with advanced NSCLC harboring METex14 skip alterations. Tepotinib, another TKI, has shown significant activity in a phase II trial and received breakthrough therapy designation from the FDA in September 2019. MET amplification (MET^Amp) and overexpression are usually a late phenomenon in tumorigenesis and aggravate malignant properties of transformed cells. Capmatinib and savolitinib have shown activity in patients with NSCLC with high levels of MET^Amp. Several other agents are being developed and under evaluation in clinical trials involving multiple tumor types. In addition to TKIs, MET overexpression is also an appealing target for development of antibody conjugated chemotherapy. Understanding the mechanisms of resistance to MET TKIs and alterations in anti-tumor immunity through MET inhibition are clinically relevant areas that need further exploration.

Prolonged survival and response to tepotinib in a non-small-cell lung cancer patient with brain metastases harboring MET exon 14 mutation: a research report

Tyrosine kinase inhibitors (TKIs) have transformed the standard of care in lung cancer. A number of TKIs have been discovered that specifically target oncogenes, including MET receptor tyrosine kinase. Second-generation MET TKIs are showing improved efficacy over first-generation TKIs. Herein, we report a case of a patient with metastatic lung adenocarcinoma harboring a MET exon 14 splice site mutation who has had prolonged disease control by a second-generation MET-TKI tepotinib. A 66-yr-old man was diagnosed with stage IV lung adenocarcinoma. He was started on carboplatin, paclitaxel, and bevacizumab, but had severe toxicity. He was switched to pembrolizumab as his tumor was PD-L1 70%, and molecular testing was not yet performed because of insufficient tissue. A bronchoscopy with endobronchial ultrasound was performed and a MET exon 14 splice site mutation was detected by next-generation sequencing. Upon progression, he was then enrolled in a clinical trial of tepotinib and continues with stable disease for more than 45 cycles and 31 mo. The MET receptor tyrosine kinase and the ligand hepatocyte growth factor (HGF) have been implicated as oncogenes and drivers of non-small-cell lung cancer (NSCLC). Newer MET TKIs including capmatinib and tepotinib more recently showed not only improved localized control and response, but early data suggests intracranial activity as compared to first-generation MET TKIs, both in the front-line and the refractory setting. This is a case report demonstrating an effective duration of response in a patient with widely metastatic lung adenocarcinoma harboring a MET exon 14 mutation.

Co-stimulatory and co-inhibitory immune markers in solid tumors with MET alterations

The implication of MET alterations in solid tumors and the immune microenvironment remains elusive. Formalin-fixed, paraffin-embedded samples of 21 patients with solid tumors harboring MET alterations were used for immunohistochemical staining. Extracted RNA was analyzed with the NanoString nCounter human PanCancer immune profiling panel (NanoString Technologies, Inc., WA, USA). Patients were diagnosed with lung (n = 10), breast (n = 5), genitourinary (n = 3) or colorectal cancer (n = 3). Eleven had a MET missense mutation, four had an exon 14 splice site mutation and six had MET amplification. CD6, CCL19, CD40LG, XCR1, MAGEA1, ATM and CCL19 genes were significantly differentially expressed in MET-altered cancers. MET alterations may have a role in various solid tumors as potential therapeutic targets and combination therapy candidates with immune checkpoint inhibitors.

MET is a receptor for growth signals that keeps cells alive and healthy. However, some tumors have changes in MET that allow for uncontrollable cell growth. Patients with MET-altered tumors may benefit from treatments targeting this gene, but eventually they become resistant to the treatments. Thus, there is a need to identify additional therapies for this patient population. The authors tested immune gene expression in tumors with MET alterations to determine if these patients would benefit from a new class of treatments called immunotherapies and found that patients with and without MET changes had differences in immune gene expression.

USP33 regulates c-Met expression by deubiquitinating SP1 to facilitate metastasis in hepatocellular carcinoma

AIMS

Deubiquitinase ubiquitin-specific protease 33 (USP33) is abnormally expressed in various tumors and participates in tumor progression. However, the expression and biological role of USP33 in hepatocellular carcinoma (HCC) are still unclear.

MAIN METHODS

We performed immunohistochemistry, western blotting, and qRT-PCR analysis to determine the expression of USP33 in HCC. We then analyzed the effects of USP33 expression on the prognosis of HCC. The roles of USP33 in regulating HCC cell migration and invasion were further explored in vitro. Animal studies were performed to investigate the effects of USP33 on tumor metastasis. RNA sequencing and luciferase reporter and immunofluorescence assays were used to identify the activation of the specificity protein 1 (SP1)/c-Met axis.

KEY FINDINGS

Here, for the first time, we reported an abnormal increase in the expression of USP33 in HCC tissues and that USP33 may act as a prognostic biomarker for HCC patients. We found that USP33 knockdown inhibited the invasion and metastasis in HCC cells both in vitro and in vivo, which was partly dependent on c-Met. Further investigations revealed that USP33 regulated c-Met expression by enhancing the protein stability of the transcription factor SP1 in HCC cells. Mechanistically, USP33 directly bound SP1 and decreased its ubiquitination, thereby upregulating c-Met expression.

SIGNIFICANCE

Our results reveal that USP33 acts as the deubiquitinating enzyme of SP1 and contributes to HCC invasion and metastasis through activation of the SP1/c-Met axis. These data indicate a previously unknown function of USP33, which may provide potential targets for the treatment of HCC patients.

HDAC1-Smad3-mSin3A complex is required for Smad3-induced transcriptional inhibition of hepatocyte growth factor receptor in human lung cancers

c-Met hyperactivity has been observed in numerous neoplasms. Several researchers have shown that the abnormal activation of c-Met is mainly caused by transcriptional activation. However, the molecular mechanism behind this transcriptional regulation is poorly understood. Here, we suggest that Smad3 negatively regulates the expression and activation of c-Met via a transcriptional mechanism. We explore the molecular mechanisms that underlie Smad3-induced c-Met transcription inhibition. We found in contrast to the high expression of c-Met, Smad3 showed low protein and mRNA levels. Smad3 and c-Met expressions were inconsistent between lung cancer tissues and cell lines. We also found that Smad3 overexpression suppresses whereas Smad3 knockdown significantly promotes Epithelial-Mesenchymal Transition and production of the angiogenic factors VEGF, CTGF and COX-2 through the ERK1/2 pathway. In addition, Smad3 overexpression decreases whereas Smad3 knockdown significantly increases protein and mRNA levels of invasion-related β-catenin and FAK through the PI3K/Akt pathway. Furthermore, using the chromatin immunoprecipitation analysis method, we demonstrate that a transcriptional regulatory complex consisting of HDAC1, Smad3 and mSin3A binds to the promoter of the c-Met gene. By either silencing endogenous mSin3A expression with siRNA or by pretreating cells with a specific HDAC1 inhibitor (MS-275), Smad3-induced transcriptional suppression of c-Met could be effectively attenuated. These results demonstrate that Smad3-induced inhibition of c-Met transcription depends on of a functional transcriptional regulatory complex that includes Smad3, mSin3A and HDAC1 at the c-Met promoter. Collectively, our findings reveal a new regulatory mechanism of c-Met signaling, and suggest a potential molecular target for the development of anticancer drugs.

CDKL2 Is Associated with HER2 Status and Overall Survival in Gastric Cancer: Comparative Analysis of CDKL2 Protein Expression and Gene Copy Number

Background

Cyclin-dependent kinase-like 2 (CDKL2) is a member of the CDKL family and recognized as a novel regulator of epithelial-mesenchymal transition of breast cancer cells, but its role has not been explored in gastric cancer (GC). This study was to characterize the CDKL2 protein expression and gene copy number in relation to human epidermal growth factor receptor 2 (HER2) status, clinicopathological features, and overall survival (OS) in GC.

Methods

This study detected the CDKL2 protein expression and gene copy number by immunochemistry (IHC) and fluorescent in situ hybridization (FISH), respectively, in 334 GC samples. HER2 status was determined according to established criteria. Associations of the CDKL2 protein expression and gene copy number with OS in GC were evaluated, and the association between CDKL2 mRNA expression and OS in GC was also analyzed using TCGA data.

Results

The detection results suggested that 34.1% cases showed high CDKL2 protein expression; 11.4% cases had ≥5 copies of CDKL2 gene or a ratio of CDKL2 to chromosome of ≥2. The CDKL2 protein expression was markedly correlated with its gene copy number. High protein expression and high gene copy number were both significantly associated with positive HER2 status, and they both could predicted a shorter OS, although not as independent markers suggested by the multivariate Cox proportional hazard regression analysis. The TCGA data indicated that higher CDKL2 mRNA level also predicted a shorter OS in GC.

Conclusions

The combined detection of the CDKL2 protein level and gene copy number could be of important value in predicting HER2 status and prognosis of patients with GC.

EGFR/c-Met and mTOR signaling are predictors of survival in non-small cell lung cancer

BACKGROUND

EGFR/c-Met activation/amplification and co-expression, mTOR upregulation/activation, and Akt/Wnt signaling upregulation have been individually associated with more aggressive disease and characterized as potential prognostic markers for lung cancer patients.

METHODS

Tumors obtained from 109 participants with stage I-IV non-small cell lung cancer (NSCLC) were studied for EGFR/c-Met co-localization as well as for total and active forms of EGFR, c-Met, mTOR, S6K, beta-catenin, and Axin2. Slides were graded by two independent blinded pathologists using a validated scoring system. Protein expression profile correlations were assessed using Pearson correlation and Spearman's rho. Prognosis was assessed using Kaplan-Meier analysis.

RESULTS

Protein expression profile analysis revealed significant correlations between EGFR/p-EGFR (p = 0.0412) and p-mTOR/S6K (p = 0.0044). Co-localization of p-EGFR/p-c-Met was associated with increased p-mTOR (p = 0.0006), S6K (p = 0.0018), and p-S6K (p < 0.0001) expression. In contrast, active beta-catenin was not positively correlated with EGFR/c-Met nor any activated proteins. Axin2, a negative regulator of the Wnt pathway, was correlated with EGFR, p-EGFR, p-mTOR, p-S6K, EGFR/c-Met co-localization, and p-EGFR/p-c-Met co-localization (all p-values <0.03). Kaplan-Meier analysis revealed shorter median survival in participants with high expression of Axin2, total beta-catenin, total/p-S6K, total/p-mTOR, EGFR, and EGFR/c-Met co-localization compared with low expression. After controlling for stage of disease at diagnosis, subjects with late-stage disease demonstrated shorter median survival when exhibiting high co-expression of EGFR/c-Met (8.1 month versus 22.3 month, p = 0.050), mTOR (6.7 month versus 22.3 month, p = 0.002), and p-mTOR (8.1 month versus 25.4 month, p = 0.004) compared with low levels.

CONCLUSIONS

These findings suggest that increased EGFR/c-Met signaling is correlated with upregulated mTOR/S6K signaling, which may in turn be associated with shorter median survival in late-stage NSCLC.

The analysis of surgical prognostic factors and molecular typing of locally advanced lung squamous cell carcinomas

Lung squamous cell carcinoma (LSCC) is a common subtype of non-small cell lung cancer (NSCLC), accounts for about 30% of all lung cancer, and has unique clinical and histologic characteristics. The predominant treatment of LSCC is surgical intervention. The purpose of this study was to explore the survival rates of the patients with primary LSCC after surgical treatment and the factors affecting prognosis. And also to analyze the molecular typing of local advanced LSCC of patients with various survival periods. We retrospectively evaluated the files of 170 patients with squamous NSCLC who were treated at the Department of Lung Cancer Surgery, Tianjin Medical University General Hospital, between January 2008 and December 2011. Univariate (Cox regression analysis) and multivariate (likelihood ratio) analyses were carried out for overall survival (OS) and the median survival duration. A P-value of < .05 was defined as significant. And then, we detected the mutation of 56 genes related to lung cancer by next-generation sequencing for two groups of lung squamous cell cancer patients, in which the OS was more than 3 years in one group and less than 1 year in the other group. In addition, we analysis the relationship between the molecular typing and the survival period. Next, we used the Cancer Genome Atlas (TCGA) database to compare the different patients' clinical information with the genes, which have been analyzed in our patients' tumor tissue samples.

Emerging MET tyrosine kinase inhibitors for the treatment of non-small cell lung cancer

Introduction MET aberrations, including MET exon 14 skipping mutation and amplification, are present in ~5% of non-small cell lung cancer (NSCLC) cases, and these levels are comparable to the frequency of ALK fusion. MET amplification also occurs as an acquired resistance mechanism in EGFR-mutated NSCLC after EGFR tyrosine kinase inhibitors (TKI) treatment failure. Therefore, the development of therapies for activated MET is urgently needed. Areas covered This review summarizes (1) the mechanisms and frequencies of MET aberrations in NSCLC, (2) the efficacies and toxicities of MET-TKIs under clinical development and (3) the mechanisms of inherent and acquired resistance to MET-TKIs. Expert opinion Type Ia, Ib and II MET-TKIs are currently under clinical development, and phase I/II studies have shown the potent activities of tepotinib, capmatinib and savolitinib; in fact, tepotinib and capmatinib were approved for use by health authorities. However, inherent and acquired resistance through on- and off-target mechanisms has been detected, and strategies to overcome this resistance are being developed.

Characterization of MET exon 14 alteration and association with clinical outcomes of crizotinib in Chinese lung cancers

BACKGROUND

Most studies on MET exon 14 (MET-ex14) alteration, defined as an oncogenic driver, have been carried out among Caucasians; similar studies among Chinese people are limited.

METHODS

We retrospectively analyzed the genomic profiles of 11,306 Chinese patients with various stages of lung cancer to investigate the prevalence of MET-ex14. Survival outcomes were analyzed in evaluable patients who received front-line crizotinib (n = 44) or chemotherapy (n = 14).

RESULTS

MET-ex14 alterations were identified in 125 patients, a frequency of 1.1 %, which is much lower than that in Caucasians (∼2.7 %). We found that MET-ex14 alterations were more likely to be detected in older patients (median age 69.0 years, p <0.001). Among evaluable patients harboring MET-ex14 alterations, longer progression-free survival (PFS) was observed with crizotinib than with chemotherapy (8.5 months versus 4.0 months, p = 0.041), but there was no difference in overall survival (OS, 11.3 months versus 12.0 months, p = 0.66). No significant difference in PFS or OS was found among MET splice-site variants or when there were concurrent TP53 alterations. Concurrent MET amplification results in a shorter PFS (4.2 months versus 8.5 months, p = 0.029) but a comparable OS (7.8 months versus 14.0 months, p = 0.12). Patients with undetectable baseline plasma MET-ex14 had a trend of longer PFS (p = 0.097) but comparable OS (p = 0.18). A novel MET Y1003C mutation was detected and demonstrated a clinical response to crizotinib.

CONCLUSIONS

Our study demonstrated a prevalence of 1.1 % for MET-ex14 alterations among the Chinese population. Our study also contributes to a better understanding of molecular factors that are associated with clinical outcomes of patients with MET exon 14 alterations.

Dual Targeting of VEGFR2 and C-Met Kinases via the Design and Synthesis of Substituted 3-(Triazolo-thiadiazin-3-yl)indolin-2-one Derivatives as Angiogenesis Inhibitors

The vascular endothelial growth factor receptor 2 (VEGFR2) and c-mesenchymal epithelial transition factor (c-Met) are members of receptor tyrosine kinases which have a crucial role in the process of angiogenesis. Isatin moiety is a versatile group that is shared in many compounds targeting both c-Met and VEGFR2 kinases. In this study, we designed and synthesized different derivatives of substituted 3-(triazolo-thiadiazin-3-yl)indolin-2-one derivatives (6a-y) as dual inhibitors for c-Met and VEGFR2 enzymes. Eight compounds 6a, 6b, 6e, 6l, 6n, 6r, 6v, and 6y were assessed for their anticancer activities against a panel of 58 cancer cell lines according to the US-NCI protocol. Compound 6b revealed the most effective antiproliferative potency (GI %), with broad-spectrum activity against different subpanels of the most NCI 58 tumor cell lines. An in vivo hen's egg-chorioallantoic membrane (HET-CAM) angiogenic study was carried out for 21 compounds 6a, b, d, f, h, i, k-o, t, and 6x to check their mortality and toxicity. At 100 μM concentration, all compounds produced 100% mortality of the chick embryos. At 40 μM concentration, 13 compounds did not exhibit any detectable mortality (nontoxic) and revealed a potent antiangiogenic effect. Seven compounds 6b, 6d, 6f, 6n, 6o, 6t, and 6x significantly decreased the number of blood vessels, and compound 6b was the most effective antiangiogenic agent comparable to dexamethasone. Molecular docking studies were conducted for compound 6b to investigate its mode of interaction within the binding site of both c-Met and VEGFR2 kinases.

Chidamide increases the sensitivity of Non-small Cell Lung Cancer to Crizotinib by decreasing c-MET mRNA methylation

Introduction: Crizotinib is a kinase inhibitor targeting c-MET/ALK/ROS1 used as the first-line chemical for the treatment of non-small cell lung cancer (NSCLC) with ALK mutations. Although c-MET is frequently overexpressed in 35-72% of NSCLC, most NSCLCs are primarily resistant to crizotinib treatment.

Method: A set of NSCLC cell lines were used to test the effect of chidamide on the primary crizotinib resistance in vitro and in vivo. Relationships between the synergistic effect of chidamide and c-MET expression and RNA methylation were systemically studied with a battery of molecular biological assays.

Results: We found for the first time that chidamide could sensitize the effect of crizotinib in a set of ALK mutation-free NSCLC cell lines, especially those with high levels of c-MET expression. Notably, chidamide could not increase the sensitivity of NSCLC cells to crizotinib cultured in serum-free medium without hepatocyte growth factor (HGF; a c-MET ligand). In contrast, the addition of HGF into the serum-/HGF-free medium could restore the synergistic effect of chidamide. Moreover, the synergistic effect of chidamide could also be abolished either by treatment with c-MET antibody or siRNA-knockdown of c-MET expression. While cells with low or no c-MET expression were primarily resistant to chidamide-crizotinib cotreatment, enforced c-MET overexpression could increase the sensitivity of these cells to chidamide-crizotinib cotreatment. Furthermore, chidamide could decrease c-MET expression by inhibiting mRNA N6-methyladenosine (m6A) modification through the downregulation of METTL3 and WTAP expression. Chidamide-crizotinib cotreatment significantly suppressed the activity of c-MET downstream molecules.

Conclusion: Chidamide downregulated c-MET expression by decreasing its mRNA m6A methylation, subsequently increasing the crizotinib sensitivity of NSCLC cells in a c-MET-/HGF-dependent manner.

Incidence and PD-L1 Expression of MET 14 Skipping in Chinese Population: A Non-Selective NSCLC Cohort Study Using RNA-Based Sequencing

Background

Mesenchymal–epithelial transition (MET) exon14 skipping mutations represent a clinically unique molecular subtype of NSCLC. The prevalence rates of MET exon 14 skipping in lung adenocarcinoma (ADC) range from 0.9% to 4.0% in Asian populations. Since some somatic variants that do not encompass the MET exon 14 splice sites might also induce MET exon 14 skipping, the RNA-based sequencing is speculated as the most accurate method for detecting exon 14 skipping.

Patients and Methods

A total of 951 NSCLC patients from two hospitals were enrolled in this study. MET exon14 skipping was detected using RNA-based next-generation sequencing (NGS). Also, immunohistochemistry (IHC) was performed in 405 samples simultaneously.

Results

The overall estimated prevalence of MET exon 14 skipping was approximately 1.8% in ADCs and 1.7% in NSCLCs. The detection rate of MET exon 14 skipping from surgical resection specimen was 2.3% in NSCLCs and 2.0% in ADCs. The MET exon 14 skipping was identified in 6.6% of EGFR/KRAS/ALK/ROS1/RET-negative ADCs. Additionally, PD-L1 was found to be highly expressed in NSCLC patients harboring MET exon 14 skipping (P<0.01).

Conclusion

The prevalence of MET exon14 skipping in lung ADCs in the East Asian population was similar to that of the Western population as assessed by RNA-based NGS. The NSCLC patients with MET exon 14 skipping were older than those with other oncogenic driver mutations, such as EGFR, ALK, and ROS1. In addition, PD-L1 was highly expressed in NSCLC patients with MET exon 14 skipping.

Role of mTOR As an Essential Kinase in SCLC

OBJECTIVES

SCLC represents 15% of all lung cancer diagnoses in the United States and has a particularly poor prognosis. We hypothesized that kinases regulating SCLC survival pathways represent therapeutically targetable vulnerabilities whose inhibition may improve SCLC outcome.

METHODS

A short-hairpin RNA (shRNA) library targeting all human kinases was introduced in seven chemonaive patient-derived xenografts (PDX) and the cells were cultured in vitro and in vivo. On harvest, lost or depleted shRNAs were considered as regulating-cell survival pathways and deemed essential kinases.

RESULTS

Unsupervised hierarchical cluster analysis of recovered shRNAs separated the PDXs into two clusters, suggesting kinase-based heterogeneity among the SCLC PDXs. A total of 23 kinases were identified as essential in two or more PDXs, with mechanistic Target of Rapamycin (mTOR) a candidate essential kinase in four. mTOR phosphorylation status correlated with PDX sensitivity to mTOR kinase inhibition, and mTOR inhibition sensitized the PDX to cisplatin and etoposide. In the PDX in which mTOR was defined as essential, mTOR inhibition caused a 43% decrease in tumor volume at 21 days (p < 0.01). Combining mTOR inhibition with cisplatin and etoposide decreased PDX tumor volume 96% compared with cisplatin and etoposide alone at 70 days (p < 0.002). Chemoresistance did not develop with the combination of mTOR inhibition and cisplatin and etoposide in mTOR-essential PDX over 105 days. The prevalence of phospho-mTOR-Ser-2448 in a tissue microarray of chemonaive SCLC was 27%, thus, identifying an important SCLC subtype that might benefit from the addition of mTOR inhibition to standard chemotherapy.

CONCLUSIONS

These studies reveal that kinases can define SCLC subgroups, can identify therapeutic vulnerabilities, and can potentially be used to optimize therapeutic approaches. Significance We used functional genomics to identify kinases regulating SCLC survival. mTOR was identified as essential in a subset of PDXs. mTOR inhibition decreased PDX growth, sensitized PDX to cisplatin and etoposide, and prevented chemoresistance.

Targeting the MET-Signaling Pathway in Non-Small-Cell Lung Cancer: Evidence to Date

The c-MET proto-oncogene (MET) plays an important role in lung oncogenesis, affecting cancer-cell survival, growth and invasiveness. The MET receptor in non-small-cell lung cancer (NSCLC) is a potential therapeutic target. The development of high-output next-generation sequencing techniques has enabled better identification of anomalies in the MET pathway, like the MET exon-14 (METex14) mutation. Moreover, analyses of epidermal growth factor-receptor (EGFR) and mechanisms of resistance to tyrosine-kinase inhibitors (TKIs) demonstrated the importance of MET amplification as an escape mechanism in patients with TKI-treated EGFR-mutated NSCLCs. This review summarizes the laboratory findings on MET and its anomalies, trial results on METex14 alterations and MET amplification in non-EGFR mutated NSCLCs, and acquired resistance to TKI in EGFR-mutated NSCLCs. The outcomes of the first trials with anti-MET agents on non-selected NSCLC patients or those selected for MET overexpression were disappointing. Two situations seem the most promising today for the use of anti-MET agents to treat these patients: tumors harboring METex14 and those EGFR-sensitive mutation mutated under TKI-EGFR with a MET-amplification mechanism of resistance or EGFR-resistance mutation.

MET receptor in oncology: From biomarker to therapeutic target

First discovered in the 1984, the MET receptor tyrosine kinase (RTK) and its ligand hepatocyte growth factor or HGF (also known as scatter factor or SF) are implicated as key players in tumor cell migration, proliferation, and invasion in a variety of cancers. This pathway also plays a key role during embryogenesis in the development of muscular and nervous structures. High expression of the MET receptor has been shown to correlate with poor prognosis and resistance to therapy. MET exon 14 splicing variants, initially identified by us in lung cancer, is actionable through various tyrosine kinase inhibitors (TKIs). For this reason, this pathway is of interest as a therapeutic target. In this chapter we will be discussing the history of MET, the genetics of this RTK, and give some background on the receptor biology. Furthermore, we will discuss directed therapeutics, mechanisms of resistance, and the future of MET as a therapeutic target.

Non-Small Cell Lung Cancer from Genomics to Therapeutics: A Framework for Community Practice Integration to Arrive at Personalized Therapy Strategies

Non-small cell lung cancer (NSCLC) is a heterogeneous disease, and therapeutic management has advanced with the identification of various key oncogenic mutations that promote lung cancer tumorigenesis. Subsequent studies have developed targeted therapies against these oncogenes in the hope of personalizing therapy based on the molecular genomics of the tumor. This review presents approved treatments against actionable mutations in NSCLC as well as promising targets and therapies. We also discuss the current status of molecular testing practices in community oncology sites that would help to direct oncologists in lung cancer decision-making. We propose a collaborative framework between community practice and academic sites that can help improve the utilization of personalized strategies in the community, through incorporation of increased testing rates, virtual molecular tumor boards, vendor-based oncology clinical pathways, and an academic-type singular electronic health record system.

MET-dependent solid tumours - molecular diagnosis and targeted therapy

Attempts to develop MET-targeted therapies have historically focused on MET-expressing cancers, with limited success. Thus, MET expression in the absence of a genomic marker of MET dependence is a poor predictor of benefit from MET-targeted therapy. However, owing to the development of more sensitive methods of detecting genomic alterations, high-level MET amplification and activating MET mutations or fusions are all now known to be drivers of oncogenesis. MET mutations include those affecting the kinase or extracellular domains and those that result in exon 14 skipping. The activity of MET tyrosine kinase inhibitors varies by MET alteration category. The likelihood of benefit from MET-targeted therapies increases with increasing levels of MET amplification, although no consensus exists on the optimal diagnostic cut-off point for MET copy number gains identified using fluorescence in situ hybridization and, in particular, next-generation sequencing. Several agents targeting exon 14 skipping alterations are currently in clinical development, with promising data available from early-phase trials. By contrast, the therapeutic implications of MET fusions remain underexplored. Here we summarize and evaluate the utility of various diagnostic techniques and the roles of different classes of MET-targeted therapies in cancers with MET amplification, mutation and fusion, and MET overexpression.

The c-MET oncoprotein: Function, mechanisms of degradation and its targeting by novel anti-cancer agents

BACKGROUND

The c-MET oncoprotein drives cancer progression in a variety of tumors through its signaling transduction pathways. This oncoprotein is also degraded by multiple mechanisms involving the lysosome, proteasome and cleavage by proteases. Targeting c-MET degradation pathways may result in effective therapeutic strategies.

SCOPE OF REVIEW

Since the discovery of oncogenic functions of c-MET, there has been a great deal of effort to develop anti-cancer drugs targeting this oncoprotein. Unexpectedly, novel di-2-pyridylketone thiosemicarbazones that demonstrate marked anti-tumor activity, down-regulate c-MET through their ability to bind intracellular iron and via mechanisms including, down-regulation of MET mRNA, enhanced lysosomal processing and increased metalloprotease-mediated cleavage.

MAJOR CONCLUSIONS

The c-MET oncoprotein regulation and degradation pathways are complex. However, with increasing understanding of its degradation mechanisms, there is also greater opportunities to therapeutically target these pathways.

GENERAL SIGNIFICANCE

Understanding the mechanisms of degradation of c-MET protein and its regulation could lead to novel therapeutics.

Top-level MET gene copy number gain defines a subtype of poorly differentiated pulmonary adenocarcinomas with poor prognosis

Background

MET amplifications occur in human tumors, including non-small cell lung cancer (NSCLC). MET inhibitors have demonstrated some clinical activity in MET amplified NSCLC, presumably with a gene dose effect. However, the definition of MET positivity or MET amplification as a potential oncogenic driver is still under debate. In this study, we aimed to establish the molecular subgroup of NSCLC with the highest unequivocal MET amplification level and to describe the prevalence, and histologic and clinical phenotype of this subgroup.

Methods

A total of 373 unselected patients with NSCLC were consecutively tested for MET gene copy number (GCN) by FISH. Mean GCN, MET/CEN7 ratio and other FISH parameters were identified and correlated with morphological and molecular pathological characteristics of the tumors as well as with clinical data.

Results

Based on the variability of obtained data a top-level category of MET amplification was newly defined (>90th percentile of average GCN; ≥10 MET gene copies per tumor cell). This criterion was fulfilled in 2% of analyzed tumors. These tumors were exclusively poorly differentiated adenocarcinomas with a predominant solid subtype and pleomorphic features. Rarely, co-alterations were detected (KRAS mutation or MET exon 14 skipping mutation). In this top-level group, there were no EGFR mutations or ALK or ROS1 alterations. The most important clinical feature was a significantly shortened overall survival (HR 3.61; median OS 8.2 vs. 23.6 months). Worse prognosis did not depend on initial stage or treatment.

Conclusions

The newly defined top-level category of MET amplification in NSCLC defines a specific subgroup of pulmonary adenocarcinoma with adverse prognosis and characteristic morphological features. Lower levels of MET gene copy number seem to have probably no specific value as a prognostic or predictive biomarker.

Management of Non-small Cell Lung Cancer Patients with MET Exon 14 Skipping Mutations

OPINION STATEMENT

The MET exon 14 skipping mutation is found in approximately 3% of lung adenocarcinomas and slightly more than 2% of lung squamous cell carcinomas. In recent years, more and more evidence has shown that MET inhibitors have achieved good anti-tumor effect in patients with MET exon 14 skipping mutation, suggesting that MET exon 14 skipping mutation may be a new target for NSCLC patients. Patients with positive MET exon 14 skipping mutation are recommended to be administered MET inhibitors, and crizotinib is recommended by the NCCN guideline. Due to the presence of gene amplification, second site mutation, bypass activation, and pathological type transformation, one of the inevitable problems of targeted therapy is drug resistance. If type I MET inhibitors (crizotinib, capmatinib, tepotinib, savolitinib) drug resistance is developed, type II MET inhibitors (cabozantinib, glesatinib, merestinib) can be considered.

MET Oncogene in Non-Small Cell Lung Cancer: Mechanism of MET Dysregulation and Agents Targeting the HGF/c-Met Axis

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide and has a poor prognosis. Current treatments for advanced NSCLC included traditional chemotherapy, radiotherapy, targeted therapy, and immunotherapy. The efficacy of targeted therapy relies on oncogene addiction. Mesenchymal-epithelial transition factor (MET) gene can encode unconventional receptor tyrosine kinases with pleiotropic functions, when signals are abnormally activated, it can initiate and maintain tumor transformation, promote cell proliferation, survival, tumor invasion and angiogenesis. Thus, it is a promising therapeutic target. Previous studies have shown that elevated levels of HGF and/or overexpression of c-Met are associated with poor prognosis in lung cancer. In preclinical and clinical trials, c-MET inhibitors have shown some antitumor activity in NSCLC. Although the efficacy results of MET inhibitors in Phase III clinical trials are disappointing, given the molecular heterogeneity of NSCLC, only subgroups of patients with MET gene alterations may benefit from c-MET inhibitors. The challenge for the future is to screen out the potential beneficiaries. To solve this problem, there is need for large data analysis for the detection methods and treatment effects, to establish standards that meet the MET activation status, and determine reliable thresholds to achieve effective patient stratification and clinical decision making. This article summarized the structure of the hepatocyte growth factor (HGF)/c-Met axis, the different mechanisms of MET addiction, as well as MET amplification as acquired resistance mechanism to epidermal growth factor receptor-tyrosine kinase inhibitors, the latest advances of MET inhibitors, and immuotherapy in the treatment of NSCLC with MET alterations.

The Emerging Role of the c-MET-HGF Axis in Non-small Cell Lung Cancer Tumor Immunology and Immunotherapy

Study of the c-Met-HGF axis in non-small cell lung cancer (NSCLC) has focused on the roles of c-MET signaling in neoplastic epithelial cells and the secretion of its ligand hepatocyte growth factor (HGF) by tumor stromal cells. However, there is increasing evidence that some leukocyte sub-sets also express c-MET raising the possibility of an immunomodulatory role for this axis. Consequently, the role of the c-MET- HGF axis in immunoncology is an active area of ongoing research. This review summarizes current knowledge of c-MET expression in NSCLC, the prognostic significance of these findings and the mechanisms by which the c-MET-HGF axis might act in NSCLC, focusing on the emerging evidence for an immunoregulatory role.

First-in-human phase I study of BPI-9016M, a dual MET/Axl inhibitor, in patients with non-small cell lung cancer

Background

BPI-9016M is a novel small-molecule inhibitor that simultaneously targets both c-Met and AXL tyrosine kinases. This phase I study aimed to determine the maximum tolerated dose (MTD), safety, pharmacokinetics, and antitumor activity of BPI-9016M in Chinese patients with advanced non-small cell lung cancer (NSCLC).

Methods

Over the dose range of 100 mg to 800 mg, eligible patients were administered with a single dose of 9016M tablet and received 7 days of pharmacokinetics evaluation, followed by continuous dose administration (QD dosing, 28 days). Standard “3 + 3” dose escalations were performed.

Results

Twenty NSCLC patients were treated. All patients experienced at least one adverse event (AE), of which treatment-related adverse events (TRAEs) were reported in 17 (85.0%) patients. The most common TRAEs were alanine transaminase (ALT) elevation (60%), bilirubin increased (40%), dysgeusia (40%), constipation (30%), hypertension (25%), and palmar-plantar erythrodysesthesia syndrome (15%). The TRAEs of grade 3 or higher during treatment were hypertension (15%), pulmonary embolism (5%), and laryngeal pain (5%). No dose-limiting toxicity (DLT) was observed, and the MTD was not reached. The median time to C_max ranged from 2.0 to 3.5 h, and the plasma concentration of BPI-9016M declined rapidly after T_max fitting a single-compartment model. The mean AUC_0–72 h of M1 and M2-2, main metabolites of BPI-9016M, were 4.8–6.6 folds and 4.1–9.8 folds higher than that of BPI-9016M, respectively. Exposure to BPI-9016M, M1, and M2-2 reached moderate saturation at 600 mg. Among 19 evaluable patients, 1 had a partial response and 10 patients had stable disease.

Conclusion

BPI-9016M showed favorable safety and pharmacokinetic profiles, and no DLT was observed at doses up to 800 mg once daily. The promising antitumor activity in Chinese NSCLC patients supports further development of this tyrosine kinase inhibitor.

Trial registration

Clinical Trial ID: NCT02478866, registered May 21, 2015.

The efficacy and safety of onartuzumab in patients with solid cancers: A meta-analysis of randomized trials

Background

Onartuzumab, a humanized monovalent monoclonal antibody to the MET protein, has been tested in various cancers. We conducted a meta-analysis of randomized phase II and III clinical trials to investigate the efficacy and safety of onartuzumab in solid cancers.

Methods

We searched PubMed, PMC, EMBASE, and the Cochrane library databases. We included randomized phase II or III trials that evaluated the additional benefits of onartuzumab in comparison with the standard treatments. Data on progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were pooled and analyzed.

Results

From nine studies, a total of 2,138 patients were included in the meta-analysis. The addition of onartuzumab to the standard treatment resulted in no improvement of PFS (hazard ratio (HR) = 1.00 [95% confidence interval (CI), 0.90-1.11], P = 0.93) and OS (HR = 1.08 [95% CI, 0.94-1.23], P = 0.29). In the subgroup analysis with patients with non-small-cell lung cancer (NSCLC), onartuzumab was not associated with a significant improvement of OS (HR = 1.12 [95% CI, 0.93-1.34], P = 0.23) and PFS (HR = 1.05 [95% CI, 0.91-1.21], P = 0.52). With respect to AEs, onartuzumab increased the incidence of hypoalbuminemia (odds ratio (OR) = 14.8 [95% CI, 3.49-62.71], P < 0.001), peripheral edema (OR = 6.52 [95% CI, 3.60-11.81], P < 0.001), neutropenia (OR = 1.36 [95% CI, 1.03-1.79], P = 0.03), thrombocytopenia (OR = 1.98 [95% CI, 1.03-3.81], P = 0.04), and venous thrombotic events (OR = 3.05 [95% CI, 1.39-6.71], P = 0.006).

Conclusion

This meta-analysis indicates that the addition of onartuzumab to the standard treatments had no definite survival benefit with increased severe toxicities in patients with solid cancer.

Antitumor activity of crizotinib in lung cancers harboring a MET exon 14 alteration

MET exon 14 alterations are oncogenic drivers of non-small-cell lung cancers (NSCLCs)1. These alterations are associated with increased MET activity and preclinical sensitivity to MET inhibition2. Crizotinib is a multikinase inhibitor with potent activity against MET3. The antitumor activity and safety of crizotinib were assessed in 69 patients with advanced NSCLCs harboring MET exon 14 alterations. Objective response rate was 32% (95% confidence interval (CI), 21-45) among 65 response-evaluable patients. Objective responses were observed independent of the molecular heterogeneity that characterizes these cancers and did not vary by splice-site region and mutation type of the MET exon 14 alteration, concurrent increased MET copy number or the detection of a MET exon 14 alteration in circulating tumor DNA. The median duration of response was 9.1 months (95% CI, 6.4-12.7). The median progression-free survival was 7.3 months (95% CI, 5.4-9.1). MET exon 14 alteration defines a molecular subgroup of NSCLCs for which MET inhibition with crizotinib is active. These results address an unmet need for targeted therapy in people with lung cancers with MET exon 14 alterations and adds to an expanding list of genomically driven therapies for oncogenic subsets of NSCLC.

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.

Dose-escalation trial of the ALK, MET & ROS1 inhibitor, crizotinib, in patients with advanced cancer

Aim: This first-in-human, dose-finding study evaluated safety, pharmacokinetics and pharmacodynamics of crizotinib and established a recommended Phase II dose (RP2D) among patients with advanced solid malignancies. Patients & methods: Patients received oral crizotinib in a 3 + 3 dose escalation design. Results: Thirty-six patients received crizotinib (50 mg once daily-300 mg twice daily); maximum tolerated dose (and RP2D) was 250 mg twice daily. Most patients (89%) experienced ≥1 treatment-related adverse event. Three patients had grade 3 dose-limiting toxicities: alanine aminotransferase increased (n = 1) and fatigue (n = 2). Generally, an increase in soluble MET was found with increasing crizotinib concentrations. Conclusion: Crizotinib demonstrated a favorable safety profile. The observed pharmacodynamic effect on soluble MET provide evidence for targeted MET inhibition by crizotinib. Clinicaltrials. gov identifier: NCT00585195.

Targeting the MET Receptor Tyrosine Kinase as a Strategy for Radiosensitization in Locoregionally Advanced Head and Neck Squamous Cell Carcinoma

Radiotherapy (RT) along with surgery is the mainstay of treatment in head and neck squamous cell carcinoma (HNSCC). Radioresistance represents a major source of treatment failure, underlining the urgent necessity to explore and implement effective radiosensitization strategies. The MET receptor widely participates in the acquisition and maintenance of an aggressive phenotype in HNSCC and modulates the DNA damage response following ionizing radiation (IR). Here, we assessed MET expression and mutation status in primary and metastatic lesions within a cohort of patients with advanced HNSCC. Moreover, we investigated the radiosensitization potential of the MET inhibitor tepotinib in a panel of cell lines, in vitro and in vivo, as well as in ex vivo patient-derived organotypic tissue cultures (OTC). MET was highly expressed in 62.4% of primary tumors and in 53.6% of lymph node metastases (LNM), and in 6 of 9 evaluated cell lines. MET expression in primaries and LNMs was significantly associated with decreased disease control in univariate survival analyses. Tepotinib abrogated MET phosphorylation and to distinct extent MET downstream signaling. Pretreatment with tepotinib resulted in variable radiosensitization, enhanced DNA damage, cell death, and G₂-M-phase arrest. Combination of tepotinib with IR led to significant radiosensitization in one of two tested in vivo models. OTCs revealed differential patterns of response toward tepotinib, irradiation, and combination of both modalities. The molecular basis of tepotinib-mediated radiosensitization was studied by a CyTOF-based single-cell mass cytometry approach, which uncovered that MET inhibition modulated PI3K activity in cells radiosensitized by tepotinib but not in the resistant ones.

Meta-analysis of functional expression and mutational analysis of c-Met in various cancers

Comprehensive genomic profiling is expected to revolutionize cancer therapy. c-Met signaling is responsible for tumorigenesis in various cancers. In this prospective, we present the prevalence of c-Met mutations and copy number alterations across various solid tumors. We used major databases like cBioportal, PubMed, and COSMIC for c-Met mutation and amplification data collection from various cancers. Our result shows complete details about c-Met mutation and its clinical data of various cancers. Hotspot mutation of human c-Met protein reveals that repeatedly and most mutated regions and these hotspots may be a diagnostic tool for cancer confirmation. Amino acid and nucleotide changes and their prevalence were reported in a number of individual cancers. However, we collectively present the amino acid and nucleotide changes in various cancers in this review. Our collection of data for c-Met mutation and its distribution in different cancer tissue is showing that the missense mutation is the major one in all type of cancers. Copy number variation data showing amplification and deletion of human c-Met from various tumor types, lung and central nervous system tumors showing high amplification comparatively other types.

Monitoring and Determining Mitochondrial Network Parameters in Live Lung Cancer Cells

Mitochondria are dynamic organelles that constantly fuse and divide, forming dynamic tubular networks. Abnormalities in mitochondrial dynamics and morphology are linked to diverse pathological states, including cancer. Thus, alterations in mitochondrial parameters could indicate early events of disease manifestation or progression. However, finding reliable and quantitative tools for monitoring mitochondria and determining the network parameters, particularly in live cells, has proven challenging. Here, we present a 2D confocal imaging-based approach that combines automatic mitochondrial morphology and dynamics analysis with fractal analysis in live small cell lung cancer (SCLC) cells. We chose SCLC cells as a test case since they typically have very little cytoplasm, but an abundance of smaller mitochondria compared to many of the commonly used cell types. The 2D confocal images provide a robust approach to quantitatively measure mitochondrial dynamics and morphology in live cells. Furthermore, we performed 3D reconstruction of electron microscopic images and show that the 3D reconstruction of the electron microscopic images complements this approach to yield better resolution. The data also suggest that the parameters of mitochondrial dynamics and fractal dimensions are sensitive indicators of cellular response to subtle perturbations, and hence, may serve as potential markers of drug response in lung cancer.

MET Inhibitors in Small Cell Lung Cancer: From the Bench to the Bedside

Small cell lung cancer (SCLC) is the most aggressive type of lung cancer. The different systemic treatment approaches attempted in the last 35 years have not improved overall survival in the advanced stage. Targeted therapies assessed in clinical trials have failed to show efficacy against SCLC. Within the potentially interesting targets, the hepatocyte growth factor (HGF)/mesenchymal-epithelial transition (MET) pathway activation is associated with worse survival and chemoresistance in SCLC. Preclinical data suggest that the inhibition of the MET pathway can revert chemoresistance and prevent tumor growth. Recently, immunotherapy has shown modest but relevant activity in SCLC. Interestingly, MET modulation seems to be involved in increasing the efficacy of standard checkpoint inhibitors. Here, we review the preclinical and clinical data of MET inhibition in SCLC, and the role of this pathway in the immune response.

Oncogene Amplification in Growth Factor Signaling Pathways Renders Cancers Dependent on Membrane Lipid Remodeling

Advances in DNA sequencing technologies have reshaped our understanding of the molecular basis of cancer, providing a precise genomic view of tumors. Complementary biochemical and biophysical perspectives of cancer point toward profound shifts in nutrient uptake and utilization that propel tumor growth and major changes in the structure of the plasma membrane of tumor cells. The molecular mechanisms that bridge these fundamental aspects of tumor biology remain poorly understood. Here, we show that the lysophosphatidylcholine acyltransferase LPCAT1 functionally links specific genetic alterations in cancer with aberrant metabolism and plasma membrane remodeling to drive tumor growth. Growth factor receptor-driven cancers are found to depend on LPCAT1 to shape plasma membrane composition through enhanced saturated phosphatidylcholine content that is, in turn, required for the transduction of oncogenic signals. These results point to a genotype-informed strategy that prioritizes lipid remodeling pathways as therapeutic targets for diverse cancers.

First-in-Human Phase I Study of Merestinib, an Oral Multikinase Inhibitor, in Patients with Advanced Cancer

BACKGROUND

The purpose of this nonrandomized, open-label, phase I study (NCT01285037) was to evaluate the safety and tolerability of merestinib, an oral antiproliferative and antiangiogenic kinase inhibitor, and to determine a recommended phase II dose and schedule for patients with advanced cancer.

MATERIALS AND METHODS

This was a multicenter, nonrandomized, open-label, phase I study of oral merestinib consisting of six parts: dose escalation (part A), followed by a four-cohort dose-confirmation study (part B) and subsequently a four-part dose expansion and combination safety testing of merestinib with standard doses of cetuximab (part C), cisplatin (part D), gemcitabine and cisplatin (part E), and ramucirumab (part F) in patients with specific types of advanced cancers. Safety, tolerability, antitumor activity, and pharmacokinetics were evaluated in all cohorts.

RESULTS

The dose escalation, confirmation, and expansion results support the dosing of merestinib at 120 mg once daily, based on acceptable exposure and safety at this dose. One complete response was observed in a patient with cholangiocarcinoma, and three patients with cholangiocarcinoma achieved a partial response. Overall, 60 (32%) of the 186 patients enrolled in the study had a best response of stable disease.

CONCLUSION

This study demonstrates that merestinib has a tolerable safety profile and potential anticancer activity and warrants further clinical investigation.

IMPLICATIONS FOR PRACTICE

Merestinib treatment in patients with advanced cancer demonstrated an acceptable safety profile and potential antitumor activity, supporting its future development in specific disease populations as a monotherapy and/or in combination with other therapies.

Co-occurring genomic alterations in non-small-cell lung cancer biology and therapy

The impressive clinical activity of small-molecule receptor tyrosine kinase inhibitors for oncogene-addicted subgroups of non-small-cell lung cancer (for example, those driven by activating mutations in the gene encoding epidermal growth factor receptor (EGFR) or rearrangements in the genes encoding the receptor tyrosine kinases anaplastic lymphoma kinase (ALK), ROS proto-oncogene 1 (ROS1) and rearranged during transfection (RET)) has established an oncogene-centric molecular classification paradigm in this disease. However, recent studies have revealed considerable phenotypic diversity downstream of tumour-initiating oncogenes. Co-occurring genomic alterations, particularly in tumour suppressor genes such as TP53 and LKB1 (also known as STK11), have emerged as core determinants of the molecular and clinical heterogeneity of oncogene-driven lung cancer subgroups through their effects on both tumour cell-intrinsic and non-cell-autonomous cancer hallmarks. In this Review, we discuss the impact of co-mutations on the pathogenesis, biology, microenvironmental interactions and therapeutic vulnerabilities of non-small-cell lung cancer and assess the challenges and opportunities that co-mutations present for personalized anticancer therapy, as well as the expanding field of precision immunotherapy.

Verticillin A suppresses HGF-induced migration and invasion via repression of the c-Met/FAK/Src pathway in human gastric and cervical cancer cells

Background and purpose: Verticillin A is a fungal epipolythiodioxopiperazine (ETP) metabolite that was isolated from Amanita flavorubescens Alk infected by Verticillium sp. It was previously proven to possess potent anti-tumor cell growth activity, and we have recently determined that verticillin A is a selective inhibitor of H3K9me3-specific histone methyltransferase. The objective of this study was to find out whether verticillin A is an effective agent for suppression of gastric and cervical tumor progression. Materials and methods: Wound healing and transwell assays was performed to evaluate the effect of verticillin A on hepatocyte growth factor (HGF)-induced AGS and HeLa cells migration and invasion in vitro. Western blot was used to detect signaling proteins verticillin A affected. Results: We determined that verticillin A effectively suppressed hepatocyte growth factor (HGF)-induced AGS and HeLa cells migration and invasion in vitro. At the molecular level, we demonstrated that verticillin A inhibited HGF-induced c-Met phosphorylation and repressed the expression of total c-Met protein in AGS and HeLa cells, resulting from reduced expression of fatty acid synthase. In addition, verticillin A could suppress c-Met downstream FAK/Src signaling pathways by impairing c-Met phosphorylation induced by HGF. Conclusion: Our study demonstrated verticillin A inhibits the migration ability of human gastric cancer (AGS) cells and cervical cancer (HeLa) cells by targeting c-Met and its downstream FAK/Src signaling pathways, and suggested that verticillin A acts as a novel HGF/c-Met inhibitor by reducing expression of this receptor.

Sensitivity and Resistance of MET Exon 14 Mutations in Lung Cancer to Eight MET Tyrosine Kinase Inhibitors In Vitro

BACKGROUND

MNNG HOS transforming gene (MET) exon 14 mutations in lung cancer, including exon 14 skipping and point mutations, have been attracting the attention of thoracic oncologists as new therapeutic targets. Tumors with these mutations almost always acquire resistance, which also occurs in other oncogene-addicted lung cancers. However, the resistance mechanisms and treatment strategies are not fully understood.

METHODS

We generated Ba/F3 cells expressing MET exon 14 mutations by retroviral gene transfer. The sensitivities of these cells to eight MET-tyrosine kinase inhibitors (TKIs) were determined using a colorimetric assay. In addition, using N-ethyl-N-nitrosourea mutagenesis, we generated resistant clones, searched for secondary MET mutations, and then examined the sensitivities of these resistant cells to different TKIs.

RESULTS

Ba/F3 cells transfected with MET mutations grew in the absence of interleukin-3, indicating their oncogenic activity. These cells were sensitive to all MET-TKIs except tivantinib. We identified a variety of secondary mutations. D1228 and Y1230 were common sites for resistance mutations for type I TKIs, which bind the active form of MET, whereas L1195 and F1200 were common sites for type II TKIs, which bind the inactive form. In general, resistance mutations against type I were sensitive to type II, and vice versa.

CONCLUSIONS

MET-TKIs inhibited the growth of cells with MET exon 14 mutations. We also identified mutation sites specific for TKI types as resistance mechanisms and complementary activities between type I and type II inhibitors against those mutations. These finding should provide relevant clinical implication for treating patients with lung cancer harboring MET exon 14 mutations.

Evaluation of MET T1010I and MET rs40239 single-nucleotide polymorphisms in triple-negative breast cancer: a case-control study

Aim: The purpose of this study is to evaluate the role of MET T1010I and MET rs40239 as potential risk factor and/or prognostic markers in patients with triple-negative breast cancer (TNBC).

Methods: 114 samples of DNA from paraffin-embedded breast normal tissues of patients with TNBC and 124 samples of healthy controls were collected and analyzed for MET T1010I and MET rs40239 polymorphisms.

Results: MET T1010I CT genotype was associated with increased risk of TNBC in both univariate and multivariate analysis. The status of rs40239 was not associated with a higher risk for TNBC at either the univariate or the multivariate analysis. None of the examined polymorphisms was associated with overall survival at the univariate or multivariate Cox regression analysis (adjusted HR=1.35, 95% CI: 0.31–5.97 for MET T1010I CT/TT vs CC; adjusted HR=1.78, 95% CI: 0.73–4.35 for rs40239 AG/GG vs AA).

Conclusion: Our case–control study suggests that MET T1010I seems to be a risk factor for TNBC in the Caucasian Greek population, in contrast with MET rs40239, where no correlation was found.

An advanced c-MET-amplified NSCLC patient that was treated with crizotinib

Introduction

c-MET is a tyrosine kinase receptor, which is encoded in part by mesenchymal-epidermal transition (MET) exon 14. Mutations in the MET gene can cause increased c-MET signaling and oncogenic stimulation. Although c-MET mutation is rare, it is a targetable driver mutation. Although the guidelines do not recommend routine screening before treatment decision, there are drugs that can be used in patients who have c-MET mutation or amplification.

Case report

We present a metastatic c-MET-amplified non-small cell lung cancer (NSCLC) patient who was treated with crizotinib. He was not eligible for chemotherapy because of poor performance score; c-MET amplification was investigated after the other common driver mutations were negative.

Management and outcome

After c-MET amplification was shown, crizotinib 250 mg BID was started. A partial response was achieved with the initiation of crizotinib, and his performance score improved after treatment.

Discussion

We presented a metastatic c-MET-amplified NSCLC patient, who was not eligible for standard platin doublet chemotherapy, to emphasize the importance of investigating all driver mutations, including c-MET amplification especially in patients who cannot tolerate cytotoxic chemotherapy.

TGFβ-induced cytoskeletal remodeling mediates elevation of cell stiffness and invasiveness in NSCLC

Importance of growth factor (GF) signaling in cancer progression is widely acknowledged. Transforming growth factor beta (TGFβ) is known to play a key role in epithelial-to-mesenchymal transition (EMT) and metastatic cell transformation that are characterized by alterations in cell mechanical architecture and behavior towards a more robust and motile single cell phenotype. However, mechanisms mediating cancer type specific enhancement of cell mechanical phenotype in response to TGFβ remain poorly understood. Here, we combine high-throughput mechanical cell phenotyping, microarray analysis and gene-silencing to dissect cytoskeletal mediators of TGFβ-induced changes in mechanical properties of on-small-cell lung carcinoma (NSCLC) cells. Our experimental results show that elevation of rigidity and invasiveness of TGFβ-stimulated NSCLC cells correlates with upregulation of several cytoskeletal and motor proteins including vimentin, a canonical marker of EMT, and less-known unconventional myosins. Selective probing of gene-silenced cells lead to identification of unconventional myosin MYH15 as a novel mediator of elevated cell rigidity and invasiveness in TGFβ-stimulated NSCLC cells. Our experimental results provide insights into TGFβ-induced cytoskeletal remodeling of NSCLC cells and suggest that mediators of elevated cell stiffness and migratory activity such as unconventional cytoskeletal and motor proteins may represent promising pharmaceutical targets for restraining invasive spread of lung cancer.