Targeting the c-Met signaling pathway in cancer

Therapeutic implications of signaling pathways and tumor microenvironment interactions in esophageal cancer

Esophageal cancer (EC) is significantly influenced by the tumor microenvironment (TME) and altered signaling pathways. Downregulating these pathways in EC is essential for suppressing tumor development, preventing metastasis, and enhancing therapeutic outcomes. This approach can increase tumor sensitivity to treatments, enhance patient outcomes, and inhibit cancer cell proliferation and spread. The TME, comprising cellular and non-cellular elements surrounding the tumor, significantly influences EC's development, course, and treatment responsiveness. Understanding the complex relationships within the TME is crucial for developing successful EC treatments. Immunotherapy is a vital TME treatment for EC. However, the heterogeneity within the TME limits the application of anticancer drugs outside clinical settings. Therefore, identifying reliable microenvironmental biomarkers that can detect therapeutic responses before initiating therapy is crucial. Combining approaches focusing on EC signaling pathways with TME can enhance treatment outcomes. This integrated strategy aims to interfere with essential signaling pathways promoting cancer spread while disrupting factors encouraging tumor development. Unraveling aberrant signaling pathways and TME components can lead to more focused and efficient treatment approaches, identifying specific cellular targets for treatments. Targeting the TME and signaling pathways may reduce metastasis risk by interfering with mechanisms facilitating cancer cell invasion and dissemination. In conclusion, this integrative strategy has significant potential for improving patient outcomes and advancing EC research and therapy. This review discusses the altered signaling pathways and TME in EC, focusing on potential future therapeutics.

c-MET pathway in human malignancies and its targeting by natural compounds for cancer therapy

BACKGROUND

c-MET is a receptor tyrosine kinase which is classically activated by HGF to activate its downstream signaling cascades such as MAPK, PI3K/Akt/mTOR, and STAT3. The c-MET modulates cell proliferation, epithelial-mesenchymal transition (EMT), immune response, morphogenesis, apoptosis, and angiogenesis. The c-MET has been shown to serve a prominent role in embryogenesis and early development. The c-MET pathway is deregulated in a broad range of malignancies, due to overexpression of ligands or receptors, genomic amplification, and MET mutations. The link between the deregulation of c-MET signaling and tumor progression has been well-documented. Overexpression or overactivation of c-MET is associated with dismal clinical outcomes and acquired resistance to targeted therapies. Since c-MET activation results in the triggering of oncogenic pathways, abrogating the c-MET pathway is considered to be a pivotal strategy in cancer therapeutics. Herein, an analysis of role of the c-MET pathway in human cancers and its relevance in bone metastasis and therapeutic resistance has been undertaken. Also, an attempt has been made to summarize the inhibitory activity of selected natural compounds towards c-MET signaling in cancers.

METHODS

The publications related to c-MET pathway in malignancies and its natural compound modulators were obtained from databases such as PubMed, Scopus, and Google Scholar and summarized based on PRISMA guidelines. Some of the keywords used for extracting relevant literature are c-MET, natural compound inhibitors of c-MET, c-MET in liver cancer, c-MET in breast cancer, c-MET in lung cancer, c-MET in pancreatic cancer, c-MET in head and neck cancer, c-MET in bone metastasis, c-MET in therapeutic resistance, and combination of c-MET inhibitors and chemotherapeutic agents. The chemical structure of natural compounds was verified in PubChem database.

RESULTS

The search yielded 3935 publications, of which 195 reference publications were used for our analysis. Clinical trials were referenced using ClinicalTrials.gov identifier. The c-MET pathway has been recognized as a prominent target to combat the growth, metastasis, and chemotherapeutic resistance in cancers. The key role of the c-MET in bone metastasis as well as therapeutic resistance has been elaborated. Also, suppressive effect of selected natural compounds on the c-MET pathway in clinical/preclinical studies has been discussed.

Brief Report: Tepotinib as a Treatment Option in MET Exon 14 Skipping-Positive Lung Cancers-Investigating Discordance Between ArcherMET and the Oncomine Dx Target Test

Introduction

NSCLC is a leading cause of cancer-related mortality worldwide. Specific genetic alterations, such as MET exon 14 (METex14) skipping, have been identified in NSCLC, allowing targeted therapy. Tepotinib, a highly selective MET inhibitor, has displayed promise in patients with advanced NSCLC. Nevertheless, challenges arise when identifying treatment strategies for patients with discordant results regarding METex14 skipping detection between diagnostic tests.

Methods

We investigated patients with NSCLC and discordant results for METex14 skipping between the Oncomine Dx Target Test (ODxTT) and ArcherMET. Clinical response, adverse events, and the duration of tepotinib treatment were assessed, and statistical analysis was performed.

Results

Among the 19 patients deemed METex14 skipping positive by ODxTT, only 10 had concordant results with ArcherMET. The number of METex14 skipping reads detected by ODxTT was significantly lower in discordant cases. Of the 19 patients, 14 received tepotinib, and comparable response and disease control rates were observed in both concordant and discordant cases. The duration of treatment did not significantly differ between the two groups.

Conclusions

Our findings suggest that tepotinib has comparable therapeutic effects in patients with METex14 skipping-positive NSCLC irrespective of the concordance of results between ODxTT and ArcherMET. Tepotinib is a possible treatment option for patients with METex14 skipping, even in patients with discordant test results.

Emerging monoclonal antibody therapy for head and neck squamous cell carcinoma

INTRODUCTION

The incidence of head and neck squamous cell carcinoma (HNSCC) is increasing, particularly among younger populations. It is projected that the number of new cases will increase by almost 50% by 2040, with market revenues expected to triple in the same period. Despite the recent introduction of immune checkpoint inhibitors (ICIs) into the therapeutic armamentarium, the vast majority of patients with recurrent and/or metastatic (R/M) HNSCC fail to derive durable benefits from systemic therapy.

AREAS COVERED

This article aims to review the multiple monoclonal antibodies (mAbs) regimens currently under development, targeting various growth factors, immune checkpoints, immune costimulatory receptors, and more.

EXPERT OPINION

So far, the combination of anti-EGFR and ICI appears to be the most promising, especially in HPV-negative patients. It will be interesting to confirm whether the arrival of antibody-drug conjugates and bispecific mAb can surpass the efficacy of anti-EGFR, as they are also being tested in combination with ICI. Furthermore, we believe that immune costimulatory agonists and various ICIs combination are worth monitoring, despite some initial setbacks.

Expression of genes potentially involved in loss of response in patients with chronic myeloid leukemia

Chronic Myeloid Leukemia (CML) is a hematological malignancy characterized by the presence of the BCR::ABL1 fusion gene, which leads to uncontrolled cell growth and survival. Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of CML, but a significant proportion of patients develop resistance or lose response to these drugs. Understanding the molecular mechanisms underlying treatment response and resistance is crucial for improving patient outcomes. This study aimed to analyze the expression patterns of genes involved in treatment response and resistance in CML patients receiving TKI therapy. The expression levels of MET, FOXO3, p15, p16, HCK, and FYN genes were examined in CML patients and compared to healthy donors. Gene expression levels were compared between optimal responders (OR) and resistant patients (R) vs. healthy donors (HD). The MET and FOXO3 OR group showed significant differences compared with the HD, (p < 0.0001) and (p = 0.0003), respectively. p15 expression showed significant differences between OR and HD groups (p = 0.0078), while no significant differences were found in p16 expression between the HD groups. FYN showed a statistically significant difference between R vs. HD (p = 0.0157). The results of HCK expression analysis revealed significant differences between OR and HD (p = 0.0041) and between R and HD (p = 0.0026). When we analyzed OR patients with undetectable BCR::ABL1 transcripts, a greater expression of HCK was observed in the R group. These findings suggest that monitoring the expression levels of MET and FOXO3 genes could be valuable in predicting treatment response and relapse in CML patients. Our study provides important insights into the potential use of gene expression analysis as a tool for predicting treatment response and guiding treatment decisions in CML patients. This knowledge may ultimately contribute to the development of personalized treatment strategies to improve patient outcomes in CML.

Kidney cancer: Links between hereditary syndromes and sporadic tumorigenesis

Multiple hereditary syndromes predispose to kidney cancer, including Von Hippel-Lindau syndrome, BAP1-Tumor Predisposition Syndrome, Hereditary Papillary Renal Cell Carcinoma, Tuberous Sclerosis Complex, Birt-Hogg-Dubé syndrome, Hereditary Paraganglioma-Pheochromocytoma Syndrome, Fumarate Hydratase Tumor Predisposition Syndrome, and Cowden syndrome. In some cases, mutations in the genes that cause hereditary kidney cancer are tightly linked to similar histologic features in sporadic RCC. For example, clear cell RCC occurs in the hereditary syndrome VHL, and sporadic ccRCC usually has inactivation of the VHL gene. In contrast, mutations in FLCN, the causative gene for Birt-Hogg-Dube syndrome, are rarely found in sporadic RCC. Here, we focus on the genes and pathways that link hereditary and sporadic RCC.

HER3/Akt/mTOR pathway is a key therapeutic target for the reduction of triple‑negative breast cancer metastasis via the inhibition of CXCR4 expression

Triple‑negative breast cancer (TNBC), a highly metastatic subtype of breast cancer, and it has the worst prognosis among all subtypes of breast cancer. However, no effective systematic therapy is currently available for TNBC metastasis. Therefore, novel therapies targeting the key molecular mechanisms involved in TNBC metastasis are required. The present study examined whether the expression levels of human epidermal growth factor receptor 3 (HER3) were associated with the metastatic phenotype of TNBC, and evaluated the potential of HER3 as a therapeutic target in vitro and in vivo. A new highly metastatic 4T1 TNBC cell line, termed 4T1‑L8, was established. The protein expression levels in 4T1‑L8 cells were measured using luminex magnetic bead assays and western blot analysis. The HER3 expression levels and distant metastasis‑free survival (DMFS) in TNBC were analyzed using Kaplan‑Meier Plotter. Transwell migration and invasion assays were performed to detect migration and invasion. The anti‑metastatic effects were determined in an experimental mouse model of metastasis. The results revealed that the increased expression of the HER3/Akt/mTOR pathway was associated with a greater level of cell migration, invasion and metastasis of TNBC cells. In addition, it was found that high expression levels of HER3 were associated with a poor DMFS. The inhibition of the HER3/Akt/mammalian target of rapamycin (mTOR) pathway decreased the migration, invasion and metastasis of TNBC cells by decreasing the expression of C‑X‑C chemokine receptor type 4 (CXCR4). Furthermore, treatment of metastatic TNBC cells with everolimus inhibited their migration, invasion and metastasis by decreasing CXCR4 expression. Thus, targeting the HER3/Akt/mTOR pathway opens up a new avenue for the development of therapeutics against TNBC metastasis; in addition, everolimus may prove to be an effective therapeutic agent for the suppression of TNBC metastasis.

Single Inhibitors versus Dual Inhibitors: Role of HDAC in Cancer

Due to the multimodal character of cancer, inhibition of two targets simultaneously by a single molecule is a beneficial and effective approach against cancer. Histone deacetylase (HDAC) was widely investigated as a novel category of anticancer drug targets due to its crucial role in various biological processes like cell-proliferation, metastasis, and apoptosis. Numerous HDAC inhibitors such as vorinostat and panobinostat are clinically approved but have limited usage due to their low efficacy, nonselectivity, drug resistance, and toxicity. Therefore, HDACs with a dual targeting ability have attracted great attention. The strategy of combining a HDAC inhibitor with other antitumor agents has been proved advantageous for combating the nonselectivity and drug resistivity problems associated with single-target drugs. Henceforth, we have highlighted dual-targeting inhibitors to target HDAC along with topoisomerase, receptor tyrosine kinase inhibitors, and the zeste homolog 2 enzyme. Our Review mainly focuses on the impact of the substituent effect along with the linker variation of well-known HDAC-inhibitor-conjugated anticancer drugs.

The Receptor Tyrosine Kinase c-Met Promotes Lipid Accumulation in 3T3-L1 Adipocytes

The receptor tyrosine kinase c-Met is elaborated in embryogenesis, morphogenesis, metabolism, cell growth, and differentiation. JNJ38877605 (JNJ) is an inhibitor of c-Met with anti-tumor activity. The c-Met expression and its role in adipocyte differentiation are unknown. Here, we investigated the c-Met expression and phosphorylation, knockdown (KD) effects, and pharmacological inhibition of c-Met by JNJ on fat accumulation in murine preadipocyte 3T3-L1 cells. During 3T3-L1 preadipocyte differentiation, strikingly, c-Met expression at the protein and mRNA levels and the protein phosphorylation on Y1234/1235 and Y1349 is crucial for inducing its kinase catalytic activity and activating a docking site for signal transducers were increased in a time-dependent manner. Of note, JNJ treatment at 20 μM that strongly inhibits c-Met phosphorylation without altering its total expression resulted in less lipid accumulation and triglyceride (TG) content with no cytotoxicity. JNJ further reduced the expression of adipogenic regulators, including CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase (FAS), acetyl CoA carboxylase (ACC), and perilipin A. Moreover, JNJ treatment increased cAMP-activated protein kinase (AMPK) and liver kinase B-1 (LKB-1) phosphorylation but decreased ATP levels. Significantly, KD of c-Met suppressed fat accumulation and triglyceride (TG) quantity and reduced the expression of C/EBP-α, PPAR-γ, FAS, ACC, and perilipin A. Collectively, the present results demonstrate that c-Met is a novel, highly conserved mediator of adipogenesis regulating lipid accumulation in murine adipocytes.

Randomized Phase II Trial of Ficlatuzumab With or Without Cetuximab in Pan-Refractory, Recurrent/Metastatic Head and Neck Cancer

PURPOSE

Primary or acquired resistance to cetuximab, an antiepidermal growth factor receptor monoclonal antibody (mAb), minimizes its utility in recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). Aberrant hepatocyte growth factor/cMet pathway activation is an established resistance mechanism. Dual pathway targeting may overcome resistance.

PATIENTS AND METHODS

This multicenter, randomized, noncomparative phase II study evaluated ficlatuzumab, an antihepatocyte growth factor mAb, with or without cetuximab in recurrent/metastatic HNSCC. The primary end point was median progression-free survival (PFS); an arm met significance criteria if the lower bound of the 90% CI excluded the historical control of 2 months. Key eligibility criteria were HNSCC with known human papillomavirus (HPV) status, cetuximab resistance (progression within 6 months of exposure in the definitive or recurrent/metastatic setting), and resistance to platinum and anti-PD-1 mAb. Secondary end points included objective response rate (ORR), toxicity, and the association of HPV status and cMet overexpression with efficacy. Continuous Bayesian futility monitoring was used.

RESULTS

From 2018 to 2020, 60 patients were randomly assigned and 58 were treated. Twenty-seven versus 33 patients were allocated to monotherapy versus combination. Arms were balanced for major prognostic factors. The monotherapy arm closed early for futility. The combination arm met prespecified significance criteria with a median PFS of 3.7 months (lower bound 90% CI, 2.3 months; P = .04); the ORR was 6 of 32 (19%), including two complete and four partial responses. Exploratory analyses were limited to the combination arm: the median PFS was 2.3 versus 4.1 months (P = .03) and the ORR was 0 of 16 (0%) versus 6 of 16 (38%; P = .02) in the HPV-positive versus HPV-negative subgroups, respectively. cMet overexpression was associated with reduced hazard of progression in HPV-negative but not HPV-positive disease (P interaction = .02).

CONCLUSION

The ficlatuzumab-cetuximab arm met significance criteria for PFS and warrants phase III development. HPV-negative HNSCC merits consideration as a selection criterion.

Effect of Food on the Pharmacokinetics and Safety of a Novel c-Met Inhibitor SCC244: A Randomized Phase I Study in Healthy Subjects

Objective

This study aimed to investigate the effect of food on the pharmacokinetics and safety profiles of SCC244, a novel oral c-Met inhibitor in healthy Chinese male subjects.

Methods

It was a randomized, open-label, and 3-period crossover design, single-dose phase I clinical trial. A total of 18 healthy male subjects were enrolled. These subjects received a single oral 300 mg dose of SCC244 with a 14-day washout between each period. Blood samples were collected at the designated time points and determined using a validated liquid chromatography tandem mass spectrometry method. Pharmacokinetic parameters were calculated by noncompartmental methods. Tolerability was assessed by physical examination, vital sign measurements, 12-lead ECG, clinical laboratory tests, and adverse events (AEs) monitoring throughout the study.

Results

Eighteen eligible subjects were enrolled in the study. The ratios (90% CI) of C_max values for SCC244 in high-fat and low-fat meal states to that observed in fasted state were 194.8% (174.3-217.7%) and 194.6% (174.1-217.5%), respectively. The ratios of AUC_0-t and AUC_0-inf in the high-fat meal state versus the fasted state were 237.4% (208.7-270.0%) and 235.9% (207.5-268.3%), respectively. The ratios of AUC_0-t and AUC_0-inf in the low-fat meal state versus the fasted state were 219.2% (192.7-249.3%) and 218.3% (192.0-248.3%), respectively. Median T_max values and mean t_1/2 were similar in all groups. The most common AEs were headache, blood fibrinogen decreased, head discomfort, dizziness, and protein urine presence. All AEs were Common Terminology Criteria for Adverse Events (CTCAE) grade 1 (except 1 case of grade 2) and have resolved by the end of the study.

Conclusion

The bioavailability of the tablet formulation of SCC244 was significantly increased when administered with high- and low-fat meals. However, the meals did not affect the median T_max and t_1/2. Safety under different fed conditions was comparable to fasted conditions in this study.

Vascular Niche Facilitates Acquired Drug Resistance to c-Met Inhibitor in Originally Sensitive Osteosarcoma Cells

Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents characterized by drug resistance and poor prognosis. As one of the key oncogenes, c-Met is recognized as a promising therapeutic target for OS. In this report, we show that c-Met inhibitor PF02341066 specifically killed OS cells with highly phosphorylated c-Met in vitro. However, the inhibitory effect of PF02341066 was abrogated in vivo due to interference from the vascular niche. OS cells adjacent to microvessels or forming vascular mimicry suppressed c-Met expression and phosphorylation. Moreover, VEGFR2 was activated in OS cells and associated with acquired drug resistance. Dual targeting of c-Met and VEGFR2 could effectively shrink the tumor size in a xenograft model. c-Met-targeted therapy combined with VEGFR2 inhibition might be beneficial to achieve an ideal therapeutic effect in OS patients. Together, our results confirm the pivotal role of tumor heterogeneity and the microenvironment in drug response and reveal the molecular mechanism underlying acquired drug resistance to c-Met-targeted therapy.

MET gene alterations predict poor survival following chemotherapy in patients with advanced cancer

Background: To aid in oncology drug development, we investigated MET proto-oncogene receptor tyrosine kinase gene aberrations in 2,239 oncology patients who underwent next-generation sequencing (NGS) in clinical practice. Materials and methods: From November 2019 to January 2021, 2,239 patientswith advanced solid tumors who visited oncology clinics underwent NGS. The NGS panel included >500 comprehensive NGS tests using archival tissue specimens. Programmed death-ligand 1(PD-L1) 22C3 assay results and clinical records regarding initial chemotherapy were available for 1,137 (50.8%) and 1,761 (78.7%) patients, respectively for overall survival (OS) analysis. Results: The 2,239 patients represented 37 types of cancer. The NGS panel included >500 genes, microsatellite instability status, tumor mutational burden, and fusions. The most common cancer types were colorectal (N = 702), gastric (N = 481), and sarcoma (N = 180). MET aberrations were detected in 212 patients. All MET-amplified tumors had microsatellite stable status, and 8 had a high tumor mutational burden. Of 46 patients with MET-amplified cancers, 8 had MET-positive protein expression by immunohistochemistry (2+ and 3+). MET fusion was detected in 10 patients. Partner genes of MET fusion included ST7, TFEC, LRRD1, CFTR, CAV1, PCM1, HLA-DRB1, and CAPZA2. In survival analysis, patients with amplification of MET gene fusion had shorter OS and progression-free survival (PFS) than those without. Thus, MET aberration was determined to be a factor of response to chemotherapy. Conclusion: Approximately 2.1% and 0.4% of patients with advanced solid tumors demonstrated MET gene amplification and fusion, respectively, and displayed a worse response to chemotherapy and significantly shorter OS and PFS than those without MET gene amplification or fusion.

A miniaturized screening platform to identify novel regulators of extracellular matrix alignment

Extracellular matrix alignment contributes to metastasis in a number of cancers and is a known prognostic stromal factor; however, the mechanisms controlling matrix organization remain unclear. Cancer-associated fibroblasts (CAF) play a critical role in this process, particularly via matrix production and modulation of key signaling pathways controlling cell adhesion and contractility. Stroma normalization, as opposed to elimination, is a highly sought strategy, and screening for drugs that effectively alter extracellular matrix (ECM) alignment is a practical way to identify novel CAF-normalizing targets that modulate ECM organization. To meet this need, we developed a novel high-throughput screening platform in which fibroblast-derived matrices were produced in 384-well plates, imaged with automated confocal microscopy, and analyzed using a customized MATLAB script. This platform is a technical advance because it miniaturizes the assay, eliminates costly and time-consuming experimental steps, and streamlines data acquisition and analysis to enable high-throughput screening applications. As a proof of concept, this platform was used to screen a kinase inhibitor library to identify modulators of matrix alignment. A number of novel potential regulators were identified, including several receptor tyrosine kinases (c-MET, tropomyosin receptor kinase 1 (NTRK1), HER2/ERBB2) and the serine/threonine kinases protein kinase A, C, and G (PKA, PKC, and PKG). The expression of these regulators was analyzed in publicly available patient datasets to examine the association between stromal gene expression and patient outcomes.

Cryo-electron Microscopic Analysis of Single-Pass Transmembrane Receptors

Single-pass transmembrane receptors (SPTMRs) represent a diverse group of integral membrane proteins that are involved in many essential cellular processes, including signal transduction, cell adhesion, and transmembrane transport of materials. Dysregulation of the SPTMRs is linked with many human diseases. Despite extensive efforts in past decades, the mechanisms of action of the SPTMRs remain incompletely understood. One major hurdle is the lack of structures of the full-length SPTMRs in different functional states. Such structural information is difficult to obtain by traditional structural biology methods such as X-ray crystallography and nuclear magnetic resonance (NMR). The recent rapid development of single-particle cryo-electron microscopy (cryo-EM) has led to an exponential surge in the number of high-resolution structures of integral membrane proteins, including SPTMRs. Cryo-EM structures of SPTMRs solved in the past few years have tremendously improved our understanding of how SPTMRs function. In this review, we will highlight these progresses in the structural studies of SPTMRs by single-particle cryo-EM, analyze important structural details of each protein involved, and discuss their implications on the underlying mechanisms. Finally, we also briefly discuss remaining challenges and exciting opportunities in the field.

c-Met Signaling as a Therapeutic Target in Head and Neck Cancer

ABSTRACT

Despite a dearth of activating driver mutations in head and neck squamous cell carcinoma (HNSCC), aberrant activation of the oncogenes, epidermal growth factor receptor (EGFR), and c-Met is near-universal in human papillomavirus (HPV)-negative disease. Although EGFR activation drove the successful development of the anti-EGFR monoclonal antibody cetuximab in HNSCC, no c-Met-targeting therapy has gained regulatory approval. Inhibition of the c-Met pathway may subvert oncogenesis within the tumor-intrinsic compartment, blocking tumoral proliferation, invasion, migration, and metastasis, or the tumor-extrinsic compartment, modulating the immunosuppressive tumor microenvironment. This review discusses the rationale and current drug development strategies for targeting c-Met or its exclusive ligand hepatocyte growth factor (HGF) in HNSCC.

NPS-1034 Induce Cell Death with Suppression of TNFR1/NF-κB Signaling in Testicular Cancer

Background and objectives: NPS-1034 with a dual inhibitory effect on Met and Axl kinase receptors has exhibited therapeutic potential in previous models. However, no study on treating testicular cancer (TC) cell lines with NPS-1034 has been established. Materials and Methods: In this study, a series of in vitro examinations of the apoptotic effect induced by NPS-1034 in TC cell lines was conducted to clarify the molecular interactions involved. Results: A decrease in cell viability rate was observed following NPS-1034 treatment, as shown in the MTT assay. Induction of the apoptotic effect was observed in TC cells as the sub-G1 and Annexin-PI populations increased in a dose-dependent manner. The involvement of the tumor receptor necrosis factor receptor 1 (TNFR1) pathway was later determined by the proteome array and western blotting. A reduction in TNFR1 and NF-κB downstream protein expressions, an upregulation of cleaved caspase-3 and -7, and a downregulation of survivin and claspin all reassured the underlying mechanism of the TNFR1 involved in the apoptotic pathway induced by NPS-1034. Conclusions: Our findings provide evidence for a potential underlying TNFR1 pathway involved in NPS-1034 treatment. This study should offer new insights into targeted therapy for TC.

Targeting Angiogenesis in Breast Cancer: Current Evidence and Future Perspectives of Novel Anti-Angiogenic Approaches

Angiogenesis is a vital process for the growth and dissemination of solid cancers. Numerous molecular pathways are known to drive angiogenic switch in cancer cells promoting the growth of new blood vessels and increased incidence of distant metastasis. Several angiogenesis inhibitors are clinically available for the treatment of different types of advanced solid cancers. These inhibitors mostly belong to monoclonal antibodies or small-molecule tyrosine kinase inhibitors targeting the classical vascular endothelial growth factor (VEGF) and its receptors. Nevertheless, breast cancer is one example of solid tumors that had constantly failed to respond to angiogenesis inhibitors in terms of improved survival outcomes of patients. Accordingly, it is of paramount importance to assess the molecular mechanisms driving angiogenic signaling in breast cancer to explore suitable drug targets that can be further investigated in preclinical and clinical settings. This review summarizes the current evidence for the effect of clinically available anti-angiogenic drugs in breast cancer treatment. Further, major mechanisms associated with intrinsic or acquired resistance to anti-VEGF therapy are discussed. The review also describes evidence from preclinical and clinical studies on targeting novel non-VEGF angiogenic pathways in breast cancer and several approaches to the normalization of tumor vasculature by targeting pericytes, utilization of microRNAs and extracellular tumor-associate vesicles, using immunotherapeutic drugs, and nanotechnology.

Merestinib monotherapy or in combination for japanese patients with advanced and/or metastatic cancer: A phase 1 study

This phase 1, multi‐center, nonrandomized, open‐label, dose‐escalation study consisted of Part A wherein merestinib 80 or 120 mg (40‐mg tablets) was administered orally QD during a 28‐day cycle to patients diagnosed with solid tumors and Part B wherein merestinib 80 mg (40‐mg tablets) was administered orally QD, and cisplatin 25 mg/m² + gemcitabine 1000 mg/m² administered IV on Day 1 and Day 8 of a 21‐day cycle (for a maximum of eight cycles) to patients diagnosed with biliary tract carcinoma (BTC). Nineteen patients were screened and 18 patients were (Part A, n = 10; Part B, n = 8) enrolled in the trial and received treatment. All patients in Parts A and B were from Japan and were within an age range of 43–73 years, with an ECOG PS of 0.1. No dose‐limiting toxicity or deaths were experienced in the study. Dose‐limiting toxicity equivalent toxicity of Grade 4 platelet count decreased (n = 1) and was observed in Part B. In Part A, treatment‐related Grade ≥3 TEAEs were reported in one patient (PT: ALT increased and AST increased), while in Part B, five patients reported treatment‐related Grade ≥3 TEAEs with four of the five patients reporting an event of neutrophil count decreased. No complete response was reported in either Part. One patient in Part B reported partial response while four patients in each part reported stable disease. Merestinib monotherapy was concluded to be tolerable in Japanese patients, and its combination with cisplatin and gemcitabine is a tolerable regimen for Japanese patients with BTC.

Trial registration: NCT03027284 (ClinicalTrials.gov) registered on 23 January 2017.

Molecular Pathways and Druggable Targets in Head and Neck Squamous Cell Carcinoma

Head and neck cancers are a heterogeneous group of neoplasms, affecting an ever increasing global population. Despite advances in diagnostic technology and surgical approaches to manage these conditions, survival rates have only marginally improved and this has occurred mainly in developed countries. Some improvements in survival, however, have been a result of new management and treatment approaches made possible because of our ever-increasing understanding of the molecular pathways triggered in head and neck oncogenesis, and the growing understanding of the abundant heterogeneity of this group of cancers. Some important pathways are common to other solid tumours, but their impact on reducing the burden of head and neck disease has been less than impressive. Other less known and little-explored pathways may hold the key to the development of potential druggable targets. The extensive work carried out over the last decade, mostly utilising next generation sequencing has opened up the development of many novel approaches to head and neck cancer treatment. This paper explores our current understanding of the molecular pathways of this group of tumours and outlines associated druggable targets which are deployed as therapeutic approaches in head and neck oncology with the ultimate aim of improving patient outcomes and controlling the personal and economic burden of head and neck cancer.

Structural basis of the activation of c-MET receptor

The c-MET receptor is a receptor tyrosine kinase (RTK) that plays essential roles in normal cell development and motility. Aberrant activation of c-MET can lead to both tumors growth and metastatic progression of cancer cells. C-MET can be activated by either hepatocyte growth factor (HGF), or its natural isoform NK1. Here, we report the cryo-EM structures of c-MET/HGF and c-MET/NK1 complexes in the active state. The c-MET/HGF complex structure reveals that, by utilizing two distinct interfaces, one HGF molecule is sufficient to induce a specific dimerization mode of c-MET for receptor activation. The binding of heparin as well as a second HGF to the 2:1 c-MET:HGF complex further stabilize this active conformation. Distinct to HGF, NK1 forms a stable dimer, and bridges two c-METs in a symmetrical manner for activation. Collectively, our studies provide structural insights into the activation mechanisms of c-MET, and reveal how two isoforms of the same ligand use dramatically different mechanisms to activate the receptor.

Activation of c-MET receptor tyrosine kinase involves hepatocyte growth factor (HGF) and glycosaminoglycans, but the molecular mechanism is still under debate. Here, the authors present cryoEM structures of c-MET bound to two HGF splice variants and heparin, revealing the structural basis for c-MET activation.

Structure-guided design and development of novel N-phenylpyrimidin-2-amine derivatives as potential c-Met inhibitors

The HGF/Met signaling pathway is over-expressed in many types of cancers and closely related to oncogenesis and metastasis. Thus, we developed novel N-phenylpyrimidin-2-amine derivatives to test their inhibitory activities towards c-Met kinase, and most of the compounds (15a-i, 15o-r, 20 and 34a-c) could inhibit the target with IC₅₀ values from 550.8 nM to 15.0 nM. Subsequently, compound 15b, 15d, 15f, 15i, 15o, 15r, 20, 34a and 34b also showed high antiproliferative activities in c-Met sensitive tumor cell lines (PC-3, Panc-1, HepG2, HCT116 and Caki-1) with IC₅₀ values from 0.53 to 1.37 μM. The lead compound 34a displayed outstanding c-Met inhibitory activity (IC₅₀: 15.0 nM) and antiproliferative activities. Furthermore, 34a also performed favorable pharmacokinetic properties in mice (F%: 59.3) and an acceptable safety profile in preclinical studies. Further docking studies showed a common interaction of 34a with c-Met at the ATP-binding site, which indicated that 34a could be a potential candidate for c-Met inhibitors.

Impact of Preanalytical Factors on the Measurement of Tumor Tissue Biomarkers Using Immunohistochemistry

Analysis of formalin-fixed paraffin-embedded (FFPE) tissue by immunohistochemistry (IHC) is commonplace in clinical and research laboratories. However, reports suggest that IHC results can be compromised by biospecimen preanalytical factors. The National Cancer Institute's Biospecimen Preanalytical Variables Program conducted a systematic study to examine the potential effects of delay to fixation (DTF) and time in fixative (TIF) on IHC using 24 cancer biomarkers. Differences in IHC staining, relative to controls with a DTF of 1 hr, were observed in FFPE kidney tumor specimens after a DTF of ≥2 hr. Reductions in H-score and/or staining intensity were observed for c-MET, p53, PAX2, PAX8, pAKT, and survivin, whereas increases were observed for RCC1, EGFR, and CD10. Prolonged TIF of 72 hr resulted in significantly reduced H-scores of CD44 and c-Met in kidney tumor specimens, compared with controls with 12-hr TIF. An elevated probability of altered staining intensity due to DTF was observed for nine antigens, whereas for prolonged TIF an elevated probability was observed for one antigen. Results reported here and elsewhere across tumor types and antigens support limiting DTF to ≤1 hr when possible and fixing tissues in formalin for 12-24 hr to avoid confounding effects of these preanalytical factors on IHC.

Molecular Mechanisms of Hepatoblastoma

Hepatoblastoma (HB) is the predominant primary liver tumor in children. While the prognosis is favorable when the tumor can be resected, the outcome is dismal for patients with progressed HB. Therefore, a better understanding of the molecular mechanisms responsible for HB is imperative for early detection and effective treatment. Sequencing analysis of human HB specimens unraveled the pivotal role of Wnt/β-catenin pathway activation in this disease. Nonetheless, β-catenin activation alone does not suffice to induce HB, implying the need for additional alterations. Perturbations of several pathways, including Hippo, Hedgehog, NRF2/KEAP1, HGF/c-Met, NK-1R/SP, and PI3K/AKT/mTOR cascades and aberrant activation of c-MYC, n-MYC, and EZH2 proto-oncogenes, have been identified in HB, although their role requires additional investigation. Here, we summarize the current knowledge on HB molecular pathogenesis, the relevance of the preclinical findings for the human disease, and the innovative therapeutic strategies that could be beneficial for the treatment of HB patients.

Identifying a Potential Key Gene, TIMP1, Associated with Liver Metastases of Uveal Melanoma by Weight Gene Co-Expression Network Analysis

Purpose

Uveal melanoma (UM) is a primary intraocular tumor in adults, with a high percentage of metastases to the liver. Identifying potential key genes may provide information for early detection and prognosis of UM metastasis.

Patients and Methods

Differentially expressed genes (DEGs) were identified using the GSE22138 dataset. Weighted gene co-expression network analysis was used to construct co-expression modules. Functional enrichment analysis was performed for DEGs and genes of key modules. Hub genes were screened by co-expression network and protein–protein interaction network (PPI), and validated by survival analysis in The Cancer Genome Atlas database. Gene set enrichment analysis (GSEA) was used to explore the potential metastasis mechanism of UM. Transient transfection was used to investigate the effect of TIMP1 on the proliferation, migration, and invasion of UM cells.

Results

In total, 552 DEGs were identified between primary and metastatic UM and mainly enriched in extracellular matrix, cellular senescence and focal adhesion pathway. A weighted gene co‑expression network was built to identify key gene modules associated with UM metastasis (n=36). The turquoise module is positively correlated with metastasis and genes in this module were mainly enriched in peptidyl-tyrosine autophosphorylation and regulation of organ growth. The hub gene TIMP1 was screened out by co-expression network and PPI analysis. High expression of TIMP1 was related to p53 pathway by GSEA and short overall survival time. Experimental results indicated that overexpression of TIMP1 inhibited the proliferation and migration, while it had no significant effect on invasion of UM cells.

Conclusion

Our study indicates that TIMP1 might be associated with metastasis in UM, which might have important significance for identifying patients with high risk of metastasis and predicting the prognosis of UM.

Combinatorial approaches targeting the EGFR family and c-Met in SCCHN

OBJECTIVE

We aimed to develop novel combinations of inhibitors targeting EGFR family members and c-Met for the treatment of recurrent SCCHN.

MATERIALS AND METHODS

Three different c-Met inhibitors in combination with a pan-HER inhibitor (crizotinib/afatinib, tivantinib/afatinib and cabozantinib/afatinib) were investigated for their anti-tumor effects on SCCHN cell lines in vitro. In vivo activity of the combinations was tested in SCCHN cell line xenografts and patient-derived xenograft (PDX) animal models generated from patients with recurrent SCCHN.

RESULTS

Western blot assay indicated that activation of EGFR, HER2, HER3, and c-Met was blocked by all three combinations and the downstream PI3K/AKT and ERK signaling pathways were inhibited. Sulforhodamine B colorimetric assay revealed SCCHN cell growth was more effectively inhibited by the combinations than by single agents, particularly in cell lines with high c-Met expression. Furthermore, the combinations were more potent in inducing apoptosis than each of the single agents. In the PDX models, the combination treatments exhibited significantly better efficacy in tumor growth inhibition compared to the respective single agents.

CONCLUSION

In conclusion, we demonstrated that the simultaneous targeting of EGFR, HER2, and c-Met is more effective than the individual inhibition of these targets in vitro and in SCCHN cell line xenograft and PDX models. Our findings pave the way for further clinical investigation of such combinations in SCCHN.

Overexpression of enolase 2 is associated with worsened prognosis and increased glycikolysis in papillary renal cell carcinoma

Papillary renal cell carcinoma (pRCC) is characterized with underlying genetic disorders and the role enolase 2 (ENO2) in ccRCC is unknown. An in silico exploratory analysis using multiple public genetic datasets was used to establish association between ENO2 expression and clinicopathological parameters. Associations of interest were validated using 49 pRCC samples using immunohistochemistry. In vitro and in vivo assays were carried out to validate findings in tissue. ENO2 was overexpressed and prognostic in pRCC. ENO2 expression was significantly higher in younger patients and in CpG island methylator phenotype subtype. ENO2-overexpressed cases showed significant enrichment in glycolysis. Overexpression of ENO2 significantly increased proliferation and silencing of ENO2 significantly inhibited growth of ACHN cells. Glycolytic genes HK1, HK 2, and lactate dehydrogenase A were decreased when ENO2 was silenced in ACHN. Glycolytic inhibitor TT-232 showed minimal inhibitory effect on ACHN cells yet showed synergistic effect in the presence of ENO2 silencing. ENO2 significantly increased and decreased extracellular glucose, respectively in ACHN cells. Xenograft mouse model showed ENO2 silencing and TT-232 combination treatment showed synergistic effect in ACHN tumors. ENO2 is associated with worsened prognosis in pRCC and is related to glycolysis. ENO2-targeted therapy can be of therapeutic potential.

MET exon 14 skipping mutation, amplification and overexpression in pulmonary sarcomatoid carcinoma: A multi-center study

High frequency of MNNG HOS transforming (MET) exon 14 skipping mutation (MET exon 14Δ) has been reported in pulmonary sarcomatoid carcinomas (PSCs). However, the frequencies differ greatly. Our study aims to investigate the frequency of MET alterations and the correlations among MET exon 14Δ, amplification, and protein overexpression in a large cohort of PSCs. MET exon 14Δ, amplification, and protein overexpression were detected in 124 surgically resected PSCs by using Sanger sequencing, fluorescent in situ hybridization (FISH), and immunohistochemistry (IHC) respectively. MET exon 14Δ was identified in 9 (7.3%) of 124 cases, including 6 pleomorphic carcinomas, 2 spindle cell carcinomas and 1 carcinosarcoma. MET amplification and protein overexpression were detected in 6 PSCs (4.8%) and 25 PSCs (20.2%), respectively. MET amplification was significantly associated with overexpression (P < 0.001). However, MET exon 14Δ has no correlation with MET amplification (P = 0.370) and overexpression (P = 0.080). Multivariable analysis demonstrated that pathologic stage (hazard ratio [HR], 2.78; 95% confidence interval [CI], 1.28–6.01; P = 0.010) and MET amplification (HR, 4.71; 95% CI, 1.31–16.98; P = 0.018) were independent prognostic factors for poor median overall survival (mOS). MET alterations including MET exon 14Δ and amplification should be recommended as routine clinical testing in PSCs patients who may benefit from MET inhibitors. MET IHC appears to be an efficient screen tool for MET amplification in PSCs.

CREB5 promotes invasiveness and metastasis in colorectal cancer by directly activating MET

BACKGROUND

cAMP responsive element binding protein 5 (CREB5) is a transcriptional activator in eukaryotic cells that can regulate gene expression. Previously, we found that CREB5 was involved in the occurrence and development of colorectal cancer (CRC) using bioinformatics analysis. However, the biological roles and underlying regulatory mechanism of CREB5 in CRC remain unclear.

METHODS

Real-time PCR, western blotting, and immunohistochemistry were used to examine CREB5 expression. In vitro experiments including migration assay, wound-healing assay, chicken chorioallantoic membrane assay, and human umbilical vein endothelial cells tube formation assay were used to investigate the effects of CREB5 on CRC cell migration and tumor angiogenesis ability. Additionally, an orthotopic implantation assay was performed in nude mice to confirm the effects of CREB5 in vivo. Furthermore, gene set enrichment analysis was performed to explore the potential mechanism of CREB5 in CRC.

RESULTS

We found that CREB5 expression was highly upregulated in CRC. CREB5 overexpression was positively correlated with advanced WHO stages and TNM stages and shorter survival in CRC patients. Moreover, CREB5 overexpression promoted while CREB5 silencing reduced the invasiveness and metastatic capacity of CRC cells both in vitro and in vivo. Furthermore, CREB5 directly interacted with the MET promoter and activated the hepatocyte growth factor-MET signalling pathway. Importantly, inhibition of MET reduced the invasion and metastasis of CREB5-overexpressing CRC cells, suggesting that CREB5 promotes metastasis mainly through activation of MET signalling.

CONCLUSION

Our study demonstrates a crucial role for CREB5 in CRC metastasis by directly upregulating MET expression. CREB5 may be both a potential prognostic marker and a therapeutic target to effectively overcome metastasis in CRC.

Targeted Therapies in Advanced Biliary Tract Cancer: An Evolving Paradigm

Biliary tract cancers (BTCs) are a heterogeneous group of adenocarcinomas that originate from the epithelial lining of the biliary tree. BTCs are characterized by presentation with advanced disease precluding curative surgery, rising global incidence, and a poor prognosis. Chemotherapy is the mainstay of the current treatment, which results in a median overall survival of less than one year, underscoring the need for novel therapeutic agents and strategies. Next-generation sequencing-based molecular profiling has shed light on the underpinnings of the complex pathophysiology of BTC and has uncovered numerous actionable targets, leading to the discovery of new therapies tailored to the molecular targets. Therapies targeting fibroblast growth factor receptor (FGFR) fusion, isocitrate dehydrogenase (IDH) mutations, the human epidermal growth factor receptor (HER) family, DNA damage repair (DDR) pathways, and BRAF mutations have produced early encouraging results in selected patients. Current clinical trials evaluating targeted therapies, as monotherapies and in combination with other agents, are paving the way for novel treatment options. Genomic profiling of cell-free circulating tumor DNA that can assist in the identification of an actionable target is another exciting area of development. In this review, we provide a contemporaneous appraisal of the evolving targeted therapies and the ongoing clinical trials that will likely transform the therapeutic paradigm of BTC.

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.

Phase I Study of Ficlatuzumab and Cetuximab in Cetuximab-Resistant, Recurrent/Metastatic Head and Neck Cancer

Cetuximab, an anti-EGFR monoclonal antibody (mAb), is approved for advanced head and neck squamous cell carcinoma (HNSCC) but benefits a minority. An established tumor-intrinsic resistance mechanism is cross-talk between the EGFR and hepatocyte growth factor (HGF)/cMet pathways. Dual pathway inhibition may overcome cetuximab resistance. This Phase I study evaluated the combination of cetuximab and ficlatuzumab, an anti-HGF mAb, in patients with recurrent/metastatic HNSCC. The primary objective was to establish the recommended Phase II dose (RP2D). Secondary objectives included overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). Mechanistic tumor-intrinsic and immune biomarkers were explored. Thirteen patients enrolled with no dose-limiting toxicities observed at any dose tier. Three evaluable patients were treated at Tier 1 and nine at Tier 2, which was determined to be the RP2D (cetuximab 500 mg/m² and ficlatuzumab 20 mg/kg every 2 weeks). Median PFS and OS were 5.4 (90% CI = 1.9–11.4) and 8.9 (90% CI = 2.7–15.2) months, respectively, with a confirmed ORR of 2 of 12 (17%; 90% CI = 6–40%). High circulating soluble cMet levels correlated with poor survival. An increase in peripheral T cells, particularly the CD8⁺ subset, was associated with treatment response whereas progression was associated with expansion of a distinct myeloid population. This well-tolerated combination demonstrated promising activity in cetuximab-resistant, advanced HNSCC.

Uveal melanoma pathobiology: Metastasis to the liver

Uveal melanoma (UM) is a type of intraocular tumor with a propensity to disseminate to the liver. Despite the identification of the early driver mutations during the development of the pathology, the process of UM metastasis is still not fully comprehended. A better understanding of the genetic, molecular, and environmental factors participating to its spread and metastatic outgrowth could provide additional approaches for UM treatment. In this review, we will discuss the advances made towards the understanding of the pathogenesis of metastatic UM, summarize the current and prospective treatments, and introduce some of the ongoing research in this field.

Next-generation sequencing and histological response assessment in peritoneal metastasis from pancreatic cancer treated with PIPAC

Background

Peritoneal metastasis from pancreatic cancer (PM-PC) may be treated with repeated pressurised intraperitoneal aerosol chemotherapy (PIPAC). Utility of next-generation sequencing (NGS) to detect cancer-related mutations in peritoneal quadrant biopsies (QBs) and peritoneal fluid (PF) after systemic and PIPAC treatment has not been evaluated. Around 90% of pancreatic cancers (PCs) harbour a KRAS mutation, making PC ideal for the evaluation of this aspect.

Aims

Evaluation of PM-PC in terms of (1) histological response to PIPAC using Peritoneal Regression Grading Score (PRGS), (2) clinical characteristics and (3) frequency of mutations in QBs and PF before and after PIPAC.

Methods

Peritoneal QBs and PF were obtained prior to each PIPAC. NGS for 22 cancer-related genes was performed on primary tumours, QBs and PFs. Response was assessed by the four-tiered PRGS.

Results

Sixteen patients treated with a median of three PIPAC procedures were included. The mean PRGS was reduced from 1.91 to 1.58 (p=0.02). Fifty-seven specimens (13 primary tumours, 2 metastatic lymph nodes, 16 PFs and 26 QB sets) were analysed with NGS. KRAS mutation was found in 14/16 patients (87.50%) and in QBs, primary tumours and PF in 8/12 (66.67%), 8/13 (61.53%) and 6/9 (66.67%). The median overall survival was 9.9 months (SE 1.5, 95% CI 4.9 to 13.9).

Conclusion

PIPAC induces histological response in the majority of patients with PM-PC. KRAS mutation can be found in PM-PC after PIPAC at a frequency similar to the primaries. NGS may be used to detect predictive mutations in PM-PC of various origins, also when only post-PIPAC QBs or PFs are available.

Distinct gene expression profiles associated with clinical outcomes in patients with ovarian clear cell carcinoma and high-grade serous ovarian carcinoma

Background

Ovarian clear cell carcinoma (OCCC) is the second most common ovarian cancer after serous carcinoma in Southeast Asia. OCCC has a more unfavourable clinical outcome due to a poor response to platinum-based chemotherapy compared with serous carcinoma. The identification of biomarkers related to the prognosis of OCCC is critically important for an improved understanding of the biology that drives OCCC progression and leads to poor outcomes. To detect differences in gene expression profiles between OCCC and high-grade serous ovarian carcinoma (HGSOC), twelve patients with OCCC and twelve patients with HGSOC were recruited in whom the pathological diagnosis was confirmed on surgically resected specimens.

Results

Compared with HGSOC, OCCC has 609 differentially expression genes, and 199 are significantly different (P < 0.05). These genes are involved in the cell cycle, apoptosis, DNA damage repair, the PI3K pathway and so on. There were 164 differentially expressed genes in the PI3K pathway. There were 35 overexpressed genes in OCCC, while there were 12 overexpressed genes in HGSOC. Among these differentially expressed genes, we found that the MET gene and the CCNE1 gene were overexpressed in OCCC and associated with a worse prognosis.

Conclusions

In conclusion, there are many differentially expressed genes in OCCC and HGSOC, which indicates that the two kinds of tumours differ greatly in tumourigenesis and provides a theoretical basis for targeted therapy in the future. Further studies need to be performed to clarify the association of the differentially expressed genes with the unfavourable prognosis in OCCC.

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.

Targets for therapy in biliary tract cancers: the new horizon of personalized medicine

Biliary tract cancers (BTCs) are a set of molecularly distinct and heterogeneous diseases. While cytotoxic chemotherapy remains the current standard of care for treatment-naïve and treatment-refractory unresectable disease, recently identified mutations driving oncologic development offer opportunities for targeted therapy. Currently, alterations in the fibroblast growth factor receptor (FGFR), isocitrate dehydrogenase (IDH), v-Raf murine sarcoma viral oncogene homolog B (BRAF), DNA damage repair, and HER2 pathways have demonstrated promising new therapeutic avenues, among others, and various studies have demonstrated clinical activity with targeted tyrosine kinase inhibitors and/or antibodies. In this review, we will discuss the currently identified targets for therapy in BTCs and review currently available data regarding clinical development of treatment options in these molecularly distinct subsets.

Light-Induced Radiosynthesis of 89Zr-DFO-Azepin-Onartuzumab for Imaging the Hepatocyte Growth Factor Receptor

Methods that provide rapid access to radiolabeled antibodies are vital in the development of diagnostic and radiotherapeutic agents for PET or radioimmunotherapy. The human hepatocyte growth factor receptor (c-MET) signaling pathway is dysregulated in several malignancies, including gastric cancer, and is an important biomarker in drug discovery. Here, we used a photoradiochemical approach to produce ⁸⁹Zr-radiolabeled onartuzumab (a monovalent, antihuman c-MET antibody), starting directly from the fully formulated drug (MetMAb). Methods: Simultaneous ⁸⁹Zr-radiolabeling and protein conjugation was performed in one-pot reactions containing ⁸⁹Zr-oxalate, the photoactive chelate desferrioxamine B (DFO)-aryl azide (DFO-ArN₃), and MetMAb to give ⁸⁹Zr-DFO-azepin-onartuzumab. As a control, ⁸⁹Zr-DFO-benzyl Bn-isothiocyanate Bn-NCS-onartuzumab was prepared via a conventional two-step process using prepurified onartuzumab and DFO-Bn-NCS. Radiotracers were purified by using size-exclusion methods and evaluated by radiochromatography. Radiochemical stability was studied in human serum, and immunoreactivity was determined by cellular binding assays using MKN-45 gastric carcinoma cells. PET imaging at multiple time points (0-72 h) was performed on female athymic nude mice bearing subcutaneous MKN-45 xenografts. Biodistribution experiments were performed after the final image was obtained. The tumor specificity of ⁸⁹Zr-DFO-azepin-onartuzumab was assessed in vivo by competitive inhibition (blocking) studies. Results: Initial photoradiosynthesis experiments produced ⁸⁹Zr-DFO-azepin-onartuzumab in less than 15 min, with an isolated decay-corrected radiochemical yield (RCY) of 24.8%, a radiochemical purity of approximately 90%, and a molar activity of approximately 1.5 MBq nmol^-1 Reaction optimization improved the radiochemical conversion of ⁸⁹Zr-DFO-azepin-onartuzumab to 56.9% ± 4.1% (n = 3), with isolated RCYs of 41.2% ± 10.6% (n = 3) and radiochemical purity of more than 90%. Conventional methods produced ⁸⁹Zr-DFO-Bn-NCS-onartuzumab with an isolated RCY of more than 97%, radiochemical purity of more than 97% and molar activity of approximately 14.0 MBq nmol^-1 Both radiotracers were immunoreactive and stable in human serum. PET imaging and biodistribution studies showed high tumor uptake for both radiotracers. By 72 h, tumor and liver uptake (percentage injected dose [%ID]) reached 15.37 ± 5.21 %ID g^-1 and 6.56 ± 4.03 %ID g^-1, respectively, for ⁸⁹Zr-DFO-azepin-onartuzumab (n = 4) and 21.38 ± 11.57 %ID g^-1 and 18.84 ± 6.03 %ID g^-1, respectively, for ⁸⁹Zr-DFO-Bn-NCS-onartuzumab (n = 4). Blocking experiments gave a statistically significant reduction in tumor uptake (6.34 ± 0.47 %ID g^-1) of ⁸⁹Zr-DFO-azepin-onartuzumab (n = 4). Conclusion: The experiments demonstrated that photoradiosynthesis is a viable alternative approach for producing ⁸⁹Zr-radiolabeled antibodies directly in protein formulation buffer, reducing protein aggregation and liver uptake.

Clinicopathologic and Imaging Features of Non-Small-Cell Lung Cancer with MET Exon 14 Skipping Mutations

MET exon 14 (METex14) skipping mutations are an emerging potentially targetable oncogenic driver mutation in non-small-cell lung cancer (NSCLC). The imaging features and patterns of metastasis of NSCLC with primary METex14 skipping mutations (METex14-mutated NSCLC) are not well described. Our goal was to determine the clinicopathologic and imaging features that may suggest the presence of METex14 skipping mutations in NSCLC. This IRB-approved retrospective study included NSCLC patients with primary METex14 skipping mutations and pre-treatment imaging data between January 2013 and December 2018. The clinicopathologic characteristics were extracted from electronic medical records. The imaging features of the primary tumor and metastases were analyzed by two thoracic radiologists. In total, 84 patients with METex14-mutated NSCLC (mean age = 71.4 ± 10 years; F = 52, 61.9%, M = 32, 38.1%; smokers = 47, 56.0%, nonsmokers = 37, 44.0%) were included in the study. Most tumors were adenocarcinoma (72; 85.7%) and presented as masses (53/84; 63.1%) that were peripheral in location (62/84; 73.8%). More than one in five cancers were multifocal (19/84; 22.6%). Most patients with metastatic disease had only extrathoracic metastases (23/34; 67.6%). Fewer patients had both extrathoracic and intrathoracic metastases (10/34; 29.4%), and one patient had only intrathoracic metastases (1/34, 2.9%). The most common metastatic sites were the bones (14/34; 41.2%), the brain (7/34; 20.6%), and the adrenal glands (7/34; 20.6%). Four of the 34 patients (11.8%) had metastases only at a single site. METex14-mutated NSCLC has distinct clinicopathologic and radiologic features.

Preparation of a Novel One-Armed Anti-c-Met Antibody with Antitumor Activity Against Hepatocellular Carcinoma

Introduction

Antibody-based c-mesenchymal–epithelial transition factor (c-Met) inhibition is a promising strategy for hepatocellular carcinoma (HCC) treatment, but the intrinsic agonistic activity of the anti-c-Met antibody limits its application in drug development. Constructing a monovalent one-armed antibody has been reported to be an effective way to create an inhibitory anti-c-Met antibody.

Materials and methods

In the present study, a novel monovalent one-armed anti-c-Met antibody was constructed using the knobs-into-holes technology, and its inhibitory effects against HCC and the underlying mechanisms were explored.

Results

The one-armed anti-c-Met antibody blocked the hepatocyte growth factor (HGF)/c-Met interaction and the subsequent signal transduction, including phosphorylation of c-Met, Grb2-associated binding protein 1(Gab-1), extracellular regulated protein kinases 1/2(Erk1/2), and Akt, also referred to as protein kinase B (PKB) in HCC cell line HepG2. Furthermore, the autocrine stimulation of HepG2 cell proliferation and HGF-induced HCC cell migration were strongly inhibited by the one-armed anti-c-Met antibody. In addition, the antibody also reduced the HGF-induced proliferation and tube formation of human umbilical vein endothelial cells (HUVECs). Treating HepG2-bearing mice with the one-armed anti-c-Met antibody significantly inhibited the tumor growth in the xenograft nude mouse model.

Conclusion

The one-armed anti-c-Met antibody derived from the full-length bivalent anti-c-Met antibody might serve as a potential antitumor agent against HCC.

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.

Revascularization after angiogenesis inhibition favors new sprouting over abandoned vessel reuse

Inhibiting pathologic angiogenesis can halt disease progression, but such inhibition may offer only a temporary benefit, followed by tissue revascularization after treatment stoppage. This revascularization, however, occurs by largely unknown phenotypic changes in pathologic vessels. To investigate the dynamics of vessel reconfiguration during revascularization, we developed a model of reversible murine corneal angiogenesis permitting longitudinal examination of the same vasculature. Following 30 days of angiogenesis inhibition, two types of vascular structure were evident: partially regressed persistent vessels that were degenerate and barely functional, and fully regressed, non-functional empty basement membrane sleeves (ebms). While persistent vessels maintained a limited flow and retained collagen IV+ basement membrane, CD31+ endothelial cells (EC), and α-SMA+ pericytes, ebms were acellular and expressed only collagen IV. Upon terminating angiogenesis inhibition, transmission electron microscopy and live imaging revealed that revascularization ensued by a rapid reversal of EC degeneracy in persistent vessels, facilitating their phenotypic normalization, vasodilation, increased flow, and subsequent new angiogenic sprouting. Conversely, ebms were irreversibly sealed from the circulation by excess collagen IV deposition that inhibited EC migration and prevented their reuse. Fully and partially regressed vessels therefore have opposing roles during revascularization, where fully regressed vessels inhibit new sprouting while partially regressed persistent vessels rapidly reactivate and serve as the source of continued pathologic angiogenesis.

Icotinib-resistant HCC827 cells produce exosomes with mRNA MET oncogenes and mediate the migration and invasion of NSCLC

Background

Icotinib has been widely used in patients with non-small cell lung cancer (NSCLC), and have significantly enhanced the overall survival rate of NSCLC patients. However, acquired drug resistance limits its clinical efficacy. Tumor cell-derived exosomes have been reported to participate in various biological processes, including tumor invasion, metastasis and drug resistance.

Materials and methods

In the present study, drug resistance was measured by MTT assay. Exosomes were extracted from the cell supernatant using ultracentrifugation and identified by exosomal marker. HCC827 cells were treated with exosomes derived from icotinib-resistant (IR) HCC827 to observe the invasion and migration of parent cells. The expression of exo-mRNA was analyzed by reverse transcription-quantitative polymerase chain reaction (RT-PCR). In addition, 10 exo-mRNAs detecting from the plasma and bronchoalveolar lavage fluid (BALF) of NSCLC patients with icotinib treatment were used to establish a new drug resistant-warning formula.

Results

The oncogene MET into exosomes was identified from icotinib-resistant lung cancer cells, and this was also presented in exosomes in NSCLC patients diagnosed with cancer metastasis after icotinib treatment. The knockdown of MET in exosomes significantly decreased the ability of invasion and migration in HCC827 cells.

Conclusion

It was suggested that MET might be specifically package and transferred by exosomes to modify the invasion and migration ability of the surrounding icotinib-sensitive cells.

Long non-coding RNA SNHG4 promotes cervical cancer progression through regulating c-Met via targeting miR-148a-3p

Long non-coding RNA (lncRNA) SNHG4 has been shown to be associated with the development of a variety of cancers. The purpose of this study was to investigate the effect of SNHG4 on cervical cancer (CC) and the corresponding mechanism. The qRT-PCR was used to determine the expressions of SNHG4 and miR-148a-3p in CC cell lines and tissues. Cell apoptosis and proliferation were measured by flow cytometry and MTT assay, respectively. The interaction between SNHG4, miR-148a-3p and c-Met was verified by bioinformatics, dual-luciferase reporter gene and RNA immunoprecipitation (RIP), and the effect of SNHG4 on the growth of CC tumor in vivo was explored. The expression of SNHG4 was increased in both CC cell lines and tissues, while the expression of miR-148a-3p was down-regulated. Meanwhile, silencing SNHG4 remarkably inhibited CC cell proliferation and promoted apoptosis. In addition, miR-148a-3p was a direct target gene of SNHG4, and down-regulation of miR-148a-3p could observably reverse the effect of silencing SNHG4 on the proliferation and apoptosis of CC cells. More importantly, SNHG4 could up-regulate the expression of c-Met by targeting and interacting with miR-148a-3p. Finally, in vivo experiments confirmed that silence SNHG4 down-regulated the expression of c-Met by promoting miR-148a-3p, and ultimately suppressed the growth of CC tumor in vivo. In conclusion, SNHG4 could be used as a competitive endogenous RNA to bind to miR-148a-3p, thereby up-regulating the expression of c-Met and ultimately promoting the progression of CC, which provided a potential therapeutic target for the targeted treatment of CC.

Clinical significance of MET gene amplification in metastatic or locally advanced gastric cancer treated with first-line fluoropyrimidine and platinum combination chemotherapy

Objective

To investigate the clinical significance of MET gene amplification in patients with gastric cancer in the palliative setting.

Methods

MET amplification was assessed using fluorescence in situ hybridization (FISH) in 50 patients and quantitative polymerase chain reaction (qPCR) in 326 patients; 259 patients treated with first-line fluoropyrimidine and platinum were included for survival analysis.

Results

The results of FISH and qPCR indicated that the c-MET/CEP7 ratio was correlated with gene copy number. The optimal cutoff value for the copy number using qPCR to detect MET gene amplification with FISH was 5 (κ=0.778, P<0.001). Twenty-one out of 326 patients (6.4%) were identified asMET amplification with a copy number of >5 detected by qPCR. MET-amplified gastric cancer was associated with an Eastern Cooperative Oncology Group (ECOG) performance status (PS) score of ≥2 (33.3% vs. 10.5% P=0.007), peritoneal metastasis (76.2% vs. 46.2%, P=0.008), and elevated bilirubin levels (28.6% vs. 7.3%, P=0.006). The median overall survival (OS) and progression-free survival (PFS) were 11.9 and 5.6 months, respectively. MET-amplified gastric cancer was not associated with survival outcomes [hazard ratio (HR)=0.68, 95% confidence interval (95% CI): 0.35−1.32, P=0.254 for PFS; HR=0.68, 95% CI: 0.35−1.32, P=0.251 for OS].

Conclusions

qPCR can be used to detect MET gene amplification. MET amplification was not a predictor of poor prognosis in patients with metastatic or unresectable gastric 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.

PET Imaging of Receptor Tyrosine Kinases in Cancer

Overexpression and/or mutations of the receptor tyrosine kinase (RTK) subfamilies, such as epidermal growth factor receptors (EGFR) and vascular endothelial growth factor receptors (VEGFR), are closely associated with tumor cell growth, differentiation, proliferation, apoptosis, and cellular invasiveness. Monoclonal antibodies (mAb) and tyrosine kinase inhibitors (TKI) specifically inhibiting these RTKs have shown remarkable success in improving patient survival in many cancer types. However, poor response and even drug resistance inevitably occur. In this setting, the ability to detect and visualize RTKs with noninvasive diagnostic tools will greatly refine clinical treatment strategies for cancer patients, facilitate precise response prediction, and improve drug development. Positron emission tomography (PET) agents using targeted radioactively labeled antibodies have been developed to visualize tumor RTKs and are changing clinical decisions for certain cancer types. In the present review, we primarily focus on PET imaging of RTKs using radiolabeled antibodies with an emphasis on the clinical applications of these immunoPET probes. Mol Cancer Ther; 17(8); 1625-36. ©2018 AACR.