Research Progress in Hepatocyte Growth Factor/Mesenchymal-epithelial Transition Factor Signaling Pathway:Effects and Mechanisms on Resistance to Targeted Therapy for Non-small Cell Lung Cancer / 中国医学科学院学报

Targeted therapy is an important therapeutic method for advanced non-small cell lung cancer with driver gene alteration.However,resistance to targeted therapy will inevitably happen in clinical practice,which has become a major issue demanding prompt solution.Studies have demonstrated that bypass resistance mediated by the activation of hepatocyte growth factor(HGF)/mesenchymal-epithelial transition factor(MET)signaling pathway is a common cause of resistance to targeted therapy.Presently,relevant studies have accumulated rich experience in the specific mechanisms.To be brief,HGF/MET is an important target for overcoming the resistance to targeted therapy and promises to be a leading biomarker for judging and observing the occurrence of resistance.This paper introduces the recent studies concerning the effects and mechanisms of HGF/MET signaling pathway on resistance to targeted therapy.

MET overexpression and intratumor heterogeneity in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is among the ten most frequent and deadly cancers, without effective therapies for most patients. More recently, drugs targeting deregulated growth factor signaling receptors have been developed, such as HGF-MET targeted therapy. We assessed MET and HGF genetic alterations and gene and protein expression profiles in ESCC patients from the Brazilian National Cancer Institute and publicly available datasets, as well as the intratumor heterogeneity of the alterations found. Our analyses showed that HGF and MET genetic alterations, both copy number and mutations, are not common in ESCC, affecting 5 and 6% of the cases, respectively. HGF showed a variable mRNA expression profile between datasets, with no alterations (GSE20347), downregulation (GSE45670), and upregulation in ESCC (our dataset and GSE75241). On the other hand, MET was found consistently upregulated in ESCC compared to non-tumor surrounding tissue, with median fold-changes of 5.96 (GSE20347), 3.83 (GSE45670), 6.02 (GSE75241), and 5.0 (our dataset). Among our patients, 84% of the tumors showed at least a two-fold increase in MET expression. This observation was corroborated by protein levels, with 55% of cases exhibiting positivity in 100% of the tumor cells. Intratumor heterogeneity was evaluated in at least four tumor biopsies from five patients and two cases showed a consistent increase in MET expression (at least two-fold) in all tumor samples. Our data suggested that HGF-MET signaling pathway was likely to be overactivated in ESCC, representing a potential therapeutic target, but eligibility for this therapy should consider intratumor heterogeneity.

Neuropsychomotor developmental delay: conceptual map, term definitions, uses and limitations / Atraso do desenvolvimento neuropsicomotor: mapa conceitual, definições, usos e limitações do termo

OBJECTIVE: To retrieve the origin of the term neuropsychomotor developmental delay" (NPMD), its conceptual evolution over time, and to build a conceptual map based on literature review. DATA SOURCE: A literature search was performed in the SciELO Brazil, Web of Science, Science Direct, OneFile (GALE), Pubmed (Medline), Whiley Online, and Springer databases, from January of 1940 to January of 2013, using the following keywords: NPMD delay, NPMD retardation, developmental delay, and global developmental delay. A total of 71 articles were selected, which were used to build the conceptual map of the term. DATA SYNTHESIS: Of the 71 references, 55 were international and 16 national. The terms developmental delay and global developmental delay were the most frequently used in the international literature and, in Brazil, delayed NPMD was the most often used. The term developmental delay emerged in the mid 1940s, gaining momentum in the 1990s. In Brazil, the term delayed NPMD started to be used in the 1980s, and has been frequently cited and published in the literature. Delayed development was a characteristic of 13 morbidities described in 23 references. Regarding the type of use, 19 references were found, with seven forms of use. Among the references, 34 had definitions of the term, and 16 different concepts were identified. CONCLUSIONS: Developmental delay is addressed in the international and national literature under different names, various applications, and heterogeneous concepts. Internationally, ways to improve communication between professionals have been indicated, with standardized definition of the term and use in very specific situations up to the fifth year of life, which was not found in Brazilian publications. .

OBJETIVO: Resgatar a origem do termo atraso do desenvolvimento neuropsicomotor (DNPM), sua evolução conceitual ao longo do tempo e construir mapa conceitual do termo com base em busca bibliográfica. FONTES DE DADOS: Foi realizada busca nas bases de dados eletrônicas do Portal da Capes, que incluem Scielo Brazil, Web of Science, Science Direct, OneFile (GALE), Pubmed (Medline), Whiley Online e Springer, referente a Janeiro/1940-Janeiro/2013. Palavras-chave: atraso e retardo do DNPM, developmental delay e global developmental delay. Foram selecionados 71 artigos e construído o mapa conceitual do termo. SÍNTESE DE DADOS: Das 71 referências, 55 eram internacionais e 16 nacionais. Os termos mais encontrados foram global developmental delay e developmental delay na literatura internacional e retardo e atraso do DNPM no Brasil. Internacionalmente, o termo surgiu em meados da década de 40 ganhando força nos anos 90. No Brasil, o termo começou a ser usado na década de 80 e vem sendo frequentemente citado na literatura. O atraso é citado em 23 trabalhos como característica presente em 13 tipos de condições clínicas. Com relação ao uso, foram encontrados 19 estudos, com sete situações de uso. Dentre os artigos revisados, 34 deles apresentaram definições, sendo identificados 16 conceitos diferentes. CONCLUSÕES: O atraso do desenvolvimento é abordado na literatura internacional e nacional sob diversos nomes, diferentes aplicações e conceitos heterogêneos. Internacionalmente, apontam-se caminhos para melhorar a comunicação entre profissionais, com definição padronizada do termo e uso em situações específicas até o quinto ano de vida, o que não foi encontrado nas publicações nacionais. .

Prognostic Significance of p53, mTOR, c-Met, IGF-1R, and HSP70 Overexpression after the Resection of Hepatocellular Carcinoma

BACKGROUND/AIMS: The current study examines the expression of molecular biomarkers in hepatocellular carcinoma (HCC) and whether these findings correlate with the clinicopathologic features of the disease and patient survival. METHODS: We analyzed the immunohistochemical expression of p53, mammalian target of rapamycin (mTOR), c-Met, and insulin-like growth factor 1 receptor (IGF-1R) heat shock protein 70 (HSP70) with the clinicopathologic features of 83 HCCs. RESULTS: p53 expression was higher in the male patients with undifferentiated histological tumor grades, cirrhosis, and portal vein invasion. High 48 c-Met expression correlated with cirrhosis, and high mTOR expression correlated with the tumor grade and cirrhosis. High IGF-1R expression correlated with the tumor grade and cirrhosis. A multivariate analysis identified a significant relationship between the high expression of p53, tumor grade, and portal vein invasion. In addition, a high expression of mTOR was related to tumor grade and cirrhosis, and a high expression of HSP70 was related to portal vein invasion in a multivariate analysis. The Kaplan-Meier survival curve for patients with high versus low Edmondson grades and p53 expression was statistically significant. CONCLUSIONS: p53, mTOR, and IGF-1R expression correlated with the Edmondson tumor grade in a univariate analysis, while p53 and mTOR correlated with the Edmondson tumor grade in a multivariate analysis. In addition, the tumor grade was found to predict survival. p53 was primarily related to the clinicopathologic features compared to other markers, and it is a poor prognostic factor of survival.

Phosphoproteomic analysis identifies activated MET-axis PI3K/AKT and MAPK/ERK in lapatinib-resistant cancer cell line

Lapatinib, a dual inhibitor of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) tyrosine kinases, has shown promising results as a growth inhibitor of HER2-positive cancer cells in vitro. However, similar to other EGFR-targeting drugs, acquired resistance to lapatinib by HER2-positive cancer cells remains a major clinical challenge. To elucidate resistance mechanisms to EGFR/HER2-targeting agents, we performed a systematic quantitative comparison of the phosphoproteome of lapatinib-resistant (LR) human gastric cancer cells (SNU216-LR) versus parental cells (SNU216) using a titanium dioxide (TiO2) phosphopeptide enrichment method and analysis with a Q-Exactive hybrid quadrupole-Orbitrap mass spectrometer. Biological network analysis of differentially expressed phosphoproteins revealed apparent constitutive activation of the MET-axis phosphatidylinositide 3-kinase (PI3K)/alpha-serine/threonine-protein kinase (AKT) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathways in SNU216-LR. Inhibition of the PI3K/AKT and MAPK/ERK signaling pathways in SNU216-LR also leads to cell cycle arrest, confirming the biological network analysis. Lapatinib sensitivity was restored when cells were treated with several molecular targeting agents in combination with lapatinib. Thus, by integrating phosphoproteomic data, protein networks and effects of signaling pathway modulation on cell proliferation, we found that SNU216-LR maintains constitutive activation of the PI3K/AKT and MAPK/ERK pathways in a MET-dependent manner. These findings suggest that pathway activation is a key compensatory intracellular phospho-signaling event that may govern gastric cancer cell resistance to drug treatment.

E-cadherin and c-Met expression in actinic cheilits and lip squamous cell carcinoma

Objective: The aim of this study was to assess epithelial expression of E-cadherin and c-Met in normal lip, in actinic cheilitis and lip squamous cell carcinoma. Study Design: Biopsies of normal lip vermillion (NL, n=18), actinic cheilitis (AC, n=37), and lip SCC (n=22) were processed for E-cadherin and c-Met immunodetection. Epithelial and tumor cell expression was scored for each sample considering staining intensity and percentage. Results: E-cadherin expression was significantly reduced in AC and lip SCC as compared to normal lip (P<0.05), with a significant reduction in lip SCC as compared to AC (P=0.003). Expression of c-Met was significantly higher in AC and lip SCC as compared to NL (P<0.05), with a significant increase in lip SCC as compared to AC (P<0.0001). Conclusion: The results showed that epithelial E-cadherin expression is reduced and c-Met expression is increased as lip carcinogenesis progresses, suggesting that these proteins may be useful markers of malignant transformation.

Expresión de marcadores de proliferación celular e invasión tisular en cáncer papilar del tiroides y su asociación con metástasis ganglionares / Expression of proliferation and invasion markers in papilary thyroid carcinoma with and without lymph node involvement

Background: Several molecules that may have a role in tumor proliferation, differentiation and invasion, have been detected in thyroid carcinoma. Some of these molecules are NIS, c-MET, TIMP1 an ephrinB2. Aim: To detect the presence of these molecules in tissue samples of thyroid carcinoma and relate their expression to the biological behavior of the tumor. Material and Methods: Tissue samples were prospectively obtained from 35 patients operated for a papillary thyroid carcinoma. Twelve patients had regional lymph node involvement. NIS, c-MET, TIMP1 and EphrinB2 were detected by real time polymerase chain reaction(RT-PCR) and immunohistochemistry. Results: The expression of markers by RT-PCR was non significantly higher among tumors with lymph node involvement. Immunohistochemistryshowed a significantly lower nuclear expression and a higher cytoplasmatic expression of EphrinB2 in tumors with lymph node involvement. Conclusions: Immunohistochemical expression of EphrinB2 could be useful for the initial staging of papillary thyroid carcinoma.

Expressions and Clinical Significances of c-met, c-erbB-2, COX-2, and IL-6 in the Biliary Tract Cancers / 대한소화기학회지

BACKGROUND/AIMS: c-met, c-erbB-2, interleukin (IL)-6, and cyclooxygenase (COX)-2 expressions are considered to be implicated in the carcinogenesis and progression of cholangiocarcinoma, but the molecular pathogenesis of cholangiocarcinoma is still poorly understood. We aimed to analyze the expressions of each marker and their relationships with clinicopathologic factors. METHODS: One hundred and fourteen tissue samples were obtained from surgically resected specimens from patients with billiary tract cancer. The expressions of c-met, c-erbB-2, COX-2, and IL-6 were examined by immunohistochemically. The expression of each marker and correlations between these markers and clinicopathologic factors were analyzed. RESULTS: The expression rates of each maker were as follows: c-met 34/112 (30.4%), c-erbB-2 5/112 (4.5%), COX-2 53/113 (46.9%), and IL-6 68/113 (60.2%), respectively. c-met expression was more frequently observed in cases with invasion through the adjacent connective tissues (p=0.0263). IL-6 overexpression was more frequently observed in cases with absent lymph node metastasis (p=0.0325). Either c-erbB-2 expression or COX-2 expression was significantly associated with lymph node metastasis (p=0.0442). CONCLUSIONS: The expression of c-met was closely related to the invasiveness of cholangiocarcinoma. Co-expression of c-met, COX-2 and, IL-6 showed a significant correlation with invasiveness and lymph node metastasis and these could be useful marker to guide clinical outcome in patients with cholangiocarcinoma.

An alternatively spliced form of Met receptor is tumorigenic

The Met tyrosine kinase receptor is a widely expressed molecule, which mediates pleiotropic cellular responses following activation by its ligand, hepatocyte growth factor/scatter factor (HGF/SF). Previously, one of the authors identified an alternatively spliced form of Met (Met-SM) that lacked a single exon of a 47-amino-acid segment in the juxtamembrane domain. Here we report that Met-SM is a potent transforming gene in NIH3T3 mouse fibroblast cells. Met-SM-transfected NIH3T3 cells show stronger foci-forming activity than wild type-Met-transfected ones. In addition, Met-SM-transfected NIH3T3 cells form colonies in soft agar and are tumorigenic in athymic nu/nu mice. Furthermore, HGF/SF significantly increases the focus-forming activity of Met-SM comparing to wild type Met. The amount of protein and of tyrosine kinase activity of Met-SM accumulates to a high level following HGF/SF treatment. The accumulation of Met-SM correlated well with its delayed ubiquitination and increased stability. These results are consistent with the important role of the juxtamembrane domain in protein stability of Met receptor and suggest that the alternatively-spliced form may contribute to the development and progression of human cancer.