Research Progress of Acquired Resistance Mediated by MET Amplification in Advanced Non-small Cell Lung Cancer / 中国肺癌杂志

Mesenchymal-epithelial transition factor (MET) amplification is an important driver of resistance in epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC), and the combination of MET proto-oncogene (MET) and EGFR-tyrosine kinase inhibitors (TKIs) has shown promise in overcoming this molecularly defined acquired resistance. Emerging data also demonstrate MET amplification as a resistance driver to TKIs-treated anaplastic lymphoma kinase (ALK)-, RET-, and ROS1-fusion NSCLC. Here, we review the literature on recent research progress of MET amplification as a resistance driver to targeted therapy in oncogene-driven NSCLC and summarize the progress of clinical strategies to overcome the resistance mechanism.
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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.

MET Exon 14 Skipping Mutations in Non-small Cell Lung Cancer / 中国肺癌杂志

Recently, targeted therapy has achieved great success in the treatment of non-small cell lung cancer (NSCLC) patients. Mesenchymal to epithelial transition factor (MET) is considered to be another important molecular target for NSCLC since epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK). Accumulating clinical trials and case reports have confirmed that MET inhibitors exhibited a potential prospect in treating patients with MET 14 exon skipping alterations, suggesting that MET 14 exon skipping mutation might be an effective biomarker for MET inhibitors, which remains to be confirmed by more clinical data. This review summarizes current research about the molecular mechanism, clinicopathological characterization, treatment strategies and drug resistance mechanisms of MET 14 exon skipping alterations in NSCLC.
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Role of Recepteur D'origine Nantais on Gastric Cancer Development and Progression / 전남의대학술지

Recepteur d'origine nantais (RON) is a receptor tyrosine kinase belonging to the subfamily of which c-MET is the prototype. Large epidemiologic studies have confirmed the strong association between RON and gastric cancer development. Constitutive activation of RON signaling directly correlates with tumorigenic phenotypes of gastric cancer and a poor survival rate in advanced gastric cancer patients. In this review, we focus on recent evidence of the aberrant expression and activation of RON in gastric cancer tumors and provide insights into the mechanism of RON signaling associated with gastric cancer progression and metastasis. Current therapeutics against RON in gastric cancer are summarized.

Sobreexpresión de C-MET en carcinoma de vesícula y del tracto biliar: prevalencia y correlación clínico-molecular / Overexpression of C-MET in gallbladder and biliary tract carcinoma: prevalence and clinical-molecular correlation

El objetivo fue determinar la sobreexpresión de c-MET en pacientes con cáncer biliar y analizar asociaciones con parámetros clínicos. Este es un estudio descriptivo, longitudinal, retrospectivo y prospectivo. Se determinó la sobreexpresión por inmunohistoquímica en 58 pacientes con resultados: positivo fuerte, positivo débil y negativo. Se construyeron curvas de supervivencia global con el método de KaplanMeier en todos los pacientes y en subgrupos según estadío, género, origen tumoral y grado de diferenciación histológica. La diferencia en supervivencia global entre subgrupos se analizó por el método log-rank. La asociación entre sobreexpresión y grado de diferenciación se estudió por el método chi cuadrado. Las pruebas estadísticas se realizaron a dos colas con un valor de p 0.05. Veintinueve muestras (50%) fueron negativas, 24 (41%) positivas débiles y 5 (9%) positivas fuertes. La mediana de supervivencia fue 18.2, 11.3 y 11.7 meses en pacientes con sobreexpresión negativa, positiva débil y positiva fuerte, respectivamente. Sin embargo, la diferencia en supervivencia global entre pacientes c-MET negativos y positivos (fuerte y débil) no alcanzó significancia estadística (p 0.068). En los subgrupos los resultados fueron similares. La sobreexpresión se asoció al grado de diferenciación (p 0.015), mostrando una relación inversa; y no se correlacionó con tasa de respuesta a la quimioterapia y tiempo a la progresión. La sobreexpresión de c-MET es frecuente en cáncer biliar, se asocia al grado de diferenciación tumoral y podría tener valor pronóstico. Si la vía c-MET es importante, los fármacos inhibidores tendrían impacto en la supervivencia global (AU)

The objective was to determine the overexpression of c-MET in patients with biliary cancer and to analyze associations with clinical parameters. This is a descriptive, longitudinal, retrospective and prospective study. Overexpression was obtained by immunohistochemistry in 58 patients, with the following results: strong positive, weak positive and negative. Overall survival curves were constructed using the Kaplan-Meier method in all patients and in subgroups according to stage, gender, tumor origin and grade of histological differentiation. The difference in overall survival between groups was analyzed by the log-rank test. The association between overexpression and grade of differentiation was studied using the chisquare method. Statistical tests were two-tailed with a p value 0.05. Twenty nine samples (50%) were negative, 24 (41%) weak positive and 5 (9%) strong positive. Median survival was 18.2, 11.3 and 11.7 months in patients with negative, weak positive and strong positive overexpression, respectively. However, the difference in overall survival between negative and positive (strong and weak together) c-MET patients did not reach statistical significance (p 0.068). In the subgroup analyses the results were similar. Overexpression correlated with tumor grade (p 0.015), showing an inverse association; and was not associated neither with chemotherapy response rate nor with time to progression. Overexpression of c-MET is common in biliary cancer, is associated with grade of tumor differentiation and could have prognostic value. If the c-MET pathway is important, the inhibitory drugs would have an impact on overall survival (AU)

Expression of the c-MET, HGF and VEGF biomarkers in intestinal and diffuse gastric cancer in the Brazilian population: a pilot study for the standardization of the quantitative PCR technique

Background: Gastric carcinoma (GC) is the third leading cause of death among malignant tumors worldwide, causing approximately 900,000 deaths/year. Changes in oncogenes that encode tyrosine kinase receptors play an important role in the pathogenesis of GC. MET gene is a proto-oncogene that encodes a tyrosine kinase receptor c-MET and it is required for embryonic development and tissue repair. The hepatocyte growth factor (HGF) is the only known ligand for c-Met receptor. The MET oncogene activation suppresses apoptosis and promotes the survival, proliferation, migration, differentiation and angiogenesis of cells. Among the angiogenic factors, VEGF is the main regulator. Its biological function includes the promotion of endothelial cells mitosis to stimulate cells proliferation. These biomarkers expression in GC is relatively recent and population-based studies are required to define the expression pattern. The aim of this study was to determine qPCR technical standardization to evaluate quantitatively, in paraffin tissue samples, the presence of gene 23 expression of the MET, HGF and VEGF in diffuse and intestinal GC types. Methods: Twenty GC patients were studied, 10 patients were intestinal-type GC (average age 72.1 years) and 10 diffuse-type (average age 50.1 years). In all patients, tissue samples were analyzed from the tumor and distant areas of the tumor tissue. The relative expressions of the tumor markers c-Met, HGF and VEGF were performed by qPCR technique by comparing tumor and non-tumoral samples and they were normalized with the GAPDH constitutive gene. Statistical analysis was performed through T-test. Results: For c-Met, 18/20 (90%) patients expressed the marker and 9/20 (45%) overexpressed this gene, in which three were intestinal-type GC and six were diffuse-type GC. For HGF, only 7/20 (35%) patients expressed this gene and it was overexpressed in 4/20 (20%), in which two were intestinal-type GC and two were diffuse-type GC. For VEGF, 20/20 (100%) patients expressed this marker and in 12/20 (60%) were observed overexpression, in which eight patients had diffuse-type GC and four had intestinal-type GC. Conclusions: qPCR technique was standardized and suitable for expression analysis of the three biomarkers using paraffin embedded tissue samples. Further studies should be carried out to characterize the expression pattern of these biomarkers in GC in the Brazilian population (AU)

Role of Recepteur D'origine Nantais on Gastric Cancer Development and Progression / 전남의대학술지

Recepteur d'origine nantais (RON) is a receptor tyrosine kinase belonging to the subfamily of which c-MET is the prototype. Large epidemiologic studies have confirmed the strong association between RON and gastric cancer development. Constitutive activation of RON signaling directly correlates with tumorigenic phenotypes of gastric cancer and a poor survival rate in advanced gastric cancer patients. In this review, we focus on recent evidence of the aberrant expression and activation of RON in gastric cancer tumors and provide insights into the mechanism of RON signaling associated with gastric cancer progression and metastasis. Current therapeutics against RON in gastric cancer are summarized.

Expressions of CD44,CD47,and c-met in Ovarian Clear Cell Carcinoma and Their Clinical Significance / 中国医学科学院学报

Objective To investigate the expressions of CD44,CD47,and c-met in ovarian clear cell carcinoma (OCCC) tissue and their correlations with clinical variables and prognosis. Methods Immunohistochemical method was used to investigate the expressions of CD44,CD47,and c-met in tissues from 86 OCCC patients and the relationships of their expressions with the clinicopathological factors of OCCC were analyzed. Results The expressions of CD44,CD47,and c-met were significantly high in OCCC tissues (90.7%,91.9%,and 94.2%,respectively). The strong positive expressions of CD44 and CD47 were significantly correlated with advanced International Federation of Gynecology and Obstetrics stages,chemotherapeutic resistance,and poor prognosis (all P<0.05),the strong positive expression of c-met was significantly correlated with chemotherapeutic resistance and poor prognosis (all P<0.05),whereas there was no correlation between the strong positive expressions of CD44,CD47,and c-met and the lymphatic node metastasis. COX survival analysis revealed that advanced International Federation of Gynecology and Obstetrics stages and high expressions of CD44,CD47 and c-met were independent risk factors for poor prognosis (P<0.05). There was a positive correlation between CD44 (or CD47) and c-met and between CD44 and CD47 (the Spearman correlation coefficient rwas 0.783,0.776,and 0.835,respectively,all P<0.01). Conclusions The expressions of CD44,CD47,and c-met increase in OCCC tissues and are correlated with each other. High expressions of CD44,CD47,and c-met are independent factors for poor prognosis.

Predictive value of c-met for long-term mortality in patients with esophageal squamous cell carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the correlation of c-met protein with the clinical staging and cell differentiation of esophageal squamous cell carcinoma (ESCC).</p><p><b>METHODS</b>A total of 100 patients with ESCC were enrolled were examined for expression of c-met protein using immunohistochemistry, and the patients in negative and positive c-met expression groups were compared for clinicopathological characteristics and overall survival.</p><p><b>RESULTS</b>s The 100 ESCC patients included 67 male and 33 female patients with a median age of 59 years; 49 of the patients were negative and 51 were positive for c-met expression. Positive c-met expression was significantly correlated with advanced TMN stages and lower tumor differentiation. Kaplan-Meier survival curve showed that the median survival time of c-met-positive patients was significantly reduced compared with that of c-met-negative patients (30.9 vs 48.2 months, P<0.05). COX regression analysis showed that c-met was a independent risk factor for the overall survival of the patients (HR: 2.34, 95% CI: 1.63-4.54, P<0.05).</p><p><b>CONCLUSION</b>A positive expression of c-met protein is significantly correlated with an advanced TMN stage, lower tumor differentiation and a poor prognosis, and may serve as a indicator for predicting the prognosis of ESCC.</p>

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. .

Antiangiogenic drugs enhance the ability of invasion and metastasis of breast cancer cells under serum starvation and hypoxia / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the ability of invasion and migration of breast cancer MDA-MB-231 cells under serum starvation and hypoxia, and the effect of antiangiogenic drugs, rh-endostatin and bevacizumab, on the ability of invasion and migration of breast cancer cells under serum starvation and/or hypoxia, in order to explore the potential risk of antiangiogenic therapy in clinics.</p><p><b>METHODS</b>The cells were randomized into 4 groups, i.e., group A: 10% fetal bovine serum (FBS) group; group B: hypoxia + 10% FBS group; group C: serum starvation group; group D: hypoxia + serum starvation group; each group was further divided into three subgroups as blank control, treated with rh-endostatin and bevacizumab, respectively. Cell counting kit-8 (CCK-8) was used to assess the inhibition rate of cell growth induced by endostatin and bevacizumab, in order to determine the proper working concentration and time of the two drugs. Transwell assay was conducted to detect the cell invasion and migration in vitro. The expressions of c-Met and MMP-9 were detected by Western blot. The cells treated with rh-endostatin or bevacizumab under serum starvation were tested by hybridization using Exiqon miBase 18.0 microarray. The miRNAs which exibited significant differences (P < 0.05) in miRNA hybridization were verified by real-time PCR assay.</p><p><b>RESULTS</b>CCK-8 assay showed that the inhibition rates of MDA-MB-231 cells cultured with 800 mg/L rh-endostatin for 48 h and 24 h were (32.2 ± 2.5)% and (27.0 ± 1.3)%, respectively, showing a significant difference (P = 0.023). The inhibition rates of MDA-MB-231 cells cultured with 80 mg/L bevacizumab for 48 h and 24 h were (30.5 ± 1.4) % and (26.1 ± 2.4) %, respectively, showing also a significant difference (P = 0.015). The Transwell assay showed that in the starvation blank group, the number of invaded and penetrated cells were 28.8 ± 2.2 and 31.4 ± 1.5, respectively, significantly different from that in the rh-endostatin and bevacizumab groups (P < 0.05). The relative expressions of c-Met and MMP-9 were 0.213 ± 0.017 and 0.542 ± 0.048, respectively, with a significant difference from those of the groups treated with each drug (P < 0.05 for both). The numbers of penetrated cells in the Transwell assay treated with rh-endostatin in hypoxia were 17.5 ± 2.1 and 16.5 ± 2.8, respectively, and the numbers of penetrated cells in the Transwell assay treated with bevacizumab were 16.3 ± 3.5 and 17.5 ± 2.4, respectively, showing no significant difference among them (P > 0.05 for both). The ability of migration and invasion of MDA-MB-231 cells and the expression of c-Met and MMP-9 were not impacted by hypoxia (P > 0.05). Real-time PCR assay showed that only the levels of miR-2355 and miR375 were significantly and stably decreased in the cells which had increased ability of invasion and migration. The relative expression levels of miR375 and miR-2355 in the serum starvation blank group were 0.550 ± 0.036 and 0.852 ± 0.121, respectively, significantly lower than that in the groups treated with rh-endostatin or bevacizumab (P<0.05). In the serum starvation group, the expression levels of miR375 and miR-2355 of cells treated with rh-endostatin were 0.295 ± 0.012 and 0.253 ± 0.011, and the expression levels of cells treated with bevacizumab were 0.234 ± 0.020 and 0.309 ± 0.022, respectively, (P > 0.05 for all). Compared with the serum starvation blank group, the expression levels of miR2355 and miR375 were significantly decreased when cells were treated with rh-endostatin/bevacizumab under serum starvation, but no significant difference was found between the two drugs (P > 0.05). However, hypoxia did not affect the expressions of miR2355 and miR375 (P > 0.05).</p><p><b>CONCLUSIONS</b>The results of this study suggest that serum starvation can increase the ability of invasion and migration of breast cancer cells. Furthermore, both rh-endostatin and bevacizumab may enhance their invasion and penetration ability under serum starvation condition.</p>

Effect of bevacizumab on proliferation and invasion of human lung cancer A549 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the effect and mechanism of bevacizumab on proliferation and invasion of human lung cancer A549 cells.</p><p><b>METHODS</b>A549 cells were treated with bevacizumab. Proliferation and invasion of the bevacizumab-treated A549 cells were detected using cell counting kit CCK-8 and Transwell assay, respectively. The expression of the mRNA and protein of MMP-2, MMP-9 and c-Met were detected by real-time PCR and Western blotting, respectively.</p><p><b>RESULTS</b>Proliferation activity was inhibited at the concentration of 10 µg/ml and promoted at the concentration of 100 µg/ml bevacizumab. Bevacizumab in the concentration of 50 µg/ml had a stronger inhibitory effect on the invasion of A549 cells (16 406.19 ± 5 674.23 penetrated cells) than that of control group (36 108.68 6 263.83, P<0.05). The real-time PCR showed that bevacizumab had a stronger inhibitory effect on the expression of MMP-2 and MMP-9 mRNA at the concentration of 50 µg/ml and on the expression c-Met mRNA at the concentration of 10 µg/ml bevacizumabin the A549 cells. However bevacizumab at the concentration of 100 µg/ml showed a promoting effect on the expression of MMP-2, MMP-9 and c-Met mRNA (1.82 ± 0.31, 1.60 ± 0.25, 2.63 ± 0.48), significantly higher than that of the control group (1.00 ± 0.19, 1.00 ± 0.23, 1.00 ± 0.22, P<0.05). The expression of MMP-2, MMP-9 and c-Met mRNA and protein was inhibited by 10 µg/ml bevacizumab in a time-dependent manner. The Western blot assay showed that bevacizumab had a bi-directional effect on the expression of MMP-2 and c-Met proteins in the A549 cells: a promoting effect at 100 µg/ml and inhibitory effect on the expression of MMP-2 at 50 µg/ml bevacizumab, and inhibitory effect on the expression of c-Met protein at 10 µg/ml bevacizumab.</p><p><b>CONCLUSIONS</b>Our findings indicate that in a certain range of concentrations, bevacizumab has prominent inhibitory effect on the proliferation and invasion of A549 cells. However,over the concentration of 100 µg/ml, bevacizumab shows a weakening anti-invasion effect, even has a promoting effect on cell proliferation. This phenomenon may be related to the inhibiting effect on the expression of MMP-2 and c-Met proteins in a non-concentration-dependent manner by bevacizumab.</p>

Construction of Lentiviral Expression Vector Containing Extracellular Domain of Human Hepatocyte Growth Factor Receptor and Its Expression in 293T Cell / 生物医学工程学杂志

This research aims to construct a lentiviral expression vector carrying the extracelluar domain (ED) of human hepatocyte growth factor receptor (C-Met), and to express it in transfected 293T cells. The extracellular domain of C-Met was amplified by RT-PCR, ligated with lentiviral expression vector p RRL-CMV-ED, and then expressed in 293T cell line. The expressed protein was purified and identified by RT-PCR and Western blot. The enzyme digestion and sequence analysis showed that the lentiviral expression vector p RRL-CMV-ED was constructed correctly. The size of amplified genes was about 2 700 bp. The purified protein with Ni-affinity column was about 105 kD analyzed by SDS-PAGE. The Western blot and ELISA results showed that the expressed protein which could bind to HGF specifically was the extracelluar domain of human hepatocyte growth factor receptor. This research may lay a foundation for further study of anti-C-MET monoclonal antibody and neutralizing antibody.

Hepatocyte growth factor and male reproduction / 中华男科学杂志

The hepatocyte growth factor ( HGF) is a multifunctional growth factor, which produces multiple biological effects by binding to the c-Met acceptor. This article reviews the biological properties of HGF, particularly those correlated with male reproduction, including its abilities to promote testis embryonic development, spermatogenesis, and testosterone synthesis of Leydig cells. HGF may provide a new insight into the treatment of male hypogonadism and infertility.

Expression of c-MET in Invasive Meningioma

BACKGROUND: Meningiomas show high recurrence rates even after curative tumor removal. The invasiveness of meningiomas may contribute to their high recurrence rates. Recently, c-MET and hepatocyte growth factor (HGF) have been reported to be involved in cancer invasion. METHODS: We examined the immunohistochemical expression of c-MET and HGF in 100 cases of patients with meningiomas who have undergone complete tumor removal. RESULTS: c-MET(-High) and HGF(-High) were found in 17% and 13% of meningiomas, respectively. Brain invasion was observed in 17.6% of c-MET(-High) meningiomas, but in only 2.4% of c-MET(-Low) meningiomas (p=.033). Bone/soft tissue invasion was observed in 23.5% of c-MET(-High) meningiomas and in 9.6% of c-MET(-Low) meningiomas (p=.119). HGF(-High) did not show statistical association with brain invasion or bone/soft tissue invasion. c-MET(-High) demonstrated shorter recurrence-free survival (RFS, 93.5+/-8.2 months vs 96.1+/-1.9 months); however, this difference was not statistically significant (p=.139). There was no association of HGF(-High) with RFS. CONCLUSIONS: This study demonstrates that c-MET(-High) is associated with brain invasion of meningiomas, and that c-MET expression may be a useful predictive marker for meningioma recurrence. Patients with invasive meningiomas with high expressions of c-MET may be good candidates for targeted therapy using c-MET inhibitors.

The expression and clinical significance of OPN and C-met in laryngeal carcinoma / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To investigate the protein expression of OPN and C-met and their relationship with tumorigenesis, invasion and cancer metastasis in laryngeal squamous cell carcinoma (LSCC).@*METHOD@#The expression of OPN and C-met were detected immunohistochemical method(Elivision plus)in 52 laryngeal squamous carcinoma and 30 adjacent tissues, to analyse the relationship between their expression levels and clinical stages, differentiation grades and the metastasis of pelvic lymph nodes.@*RESULT@#The expression of OPN and C-met in laryngeal squamous carcinoma and adjacent tissues were 71.2%, 6.7% and 63.5 %,16.7%, respectively. The positive rate of OPN and C-met with LSCC in stage I-II is 48.1% and 55.6%, and that in 25 cases of stage III-IV is 96.0% and 80.0%, with significant difference among them. The positive rate of OPN is significantly lower in the cases without-metastasis of lymph node (53.6%) than that in the ones with-metastasis of lymph node (91.7%). The positive rate of C-met in the metastasis cases is 83.3%, which is much higher than that in the cases without-metastasis (46.4%). The positive rate of OPN and C-met in squamous cell carcinoma with high, medium-grade differentiation is 65.7% and 54.3%, and that in 17 cases of in squamous cell carcinoma with low-grade differentiation is 82.4%. The OPN and C-met positive rate have negative correlations with differentiation grades.@*CONCLUSION@#Expression of OPN and C-met were higher with advance of clinical stages, and it has relation to the metastasis of lymph, but it's difficult to say that there is regular relation between expression of OPN and C-met and differentiation grades. Expression of OPN and C-met have positive correlation in LSCC, and abnormal expression of OPN and C-met have some effect on tumor invasion and metastasis in LSCC patients.

NK4 growth inhibition of human Raji lymphoma xenografts by competitive interrupting HGF/Met signal pathway / 中华病理学杂志

<p><b>OBJECTIVE</b>To observe the inhibition of NK4 protein in the proliferation of human Raji lymphoma xenografts in nude mice, and to explore its molecular mechanism.</p><p><b>METHODS</b>Models of human Raji lymphoma xenograft transfected with HGF gene were established by subcutaneous inoculation in nude mice. After establishment of the models, the mice received continuous NK4 protein via tail vein for 4 weeks, and the weight and tumor growth were monitored every week. After 8 weeks, the expression of HGF mRNA and c-Met mRNA of tumor tissues was measured by real-time fluorescent quantitation PCR. The apoptotic index (AI) and microvessel density (MVD) were evaluated by terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) and immunohistochemistry, respectively.</p><p><b>RESULTS</b>The models of human Raji lymphoma xenograft were successfully established. Although the animal weights of all groups declined, especially in the groups with NK4 protein injection, there was no statistical significance (P > 0.05). The tumor volume in HGF gene transfected group was larger than those of the control groups (P < 0.01), and there was no statistical significance among the control groups (P > 0.05). However, the tumor volume of the NK4 protein injection group decreased significantly (P < 0.01). Expression of HGF mRNA and c-Met mRNA in HGF gene transfected group increased significantly after injection of NK4 protein (P < 0.01). AI in HGF gene transfected group (33.5% ± 12.3%) was significantly lower than that of control groups (89.1% ± 22.3% vs. 81.9% ± 27.0%, P < 0.05), but became significantly higher (119.1% ± 18.9%) after NK4 protein injection (P < 0.01). MVD in HGF gene transfected group (28.5 ± 2.0) was higher than that of control groups (12.2 ± 1.4, 13.8 ± 1.3, P < 0.01), although declined (15.5 ± 2.5) after NK4 protein injection (P < 0.01).</p><p><b>CONCLUSIONS</b>NK4 protein suppresses significantly the growth of human Raji lymphoma xenografts transfected with HGF gene. The pathogenesis may be involved in promoting tumor cell apoptosis and restraining tumor angiogenesis through competitive interrupting HGF/Met signal pathway.</p>

A putative pH-dependent nuclear localization signal in the juxtamembrane region of c-Met

The C-terminal fragment of the c-Met receptor tyrosine kinase is present in the nuclei of some cells irrespective of ligand stimulation, but the responsible nuclear localization signal (NLS) has not been previously reported. Here, we report that two histidine residues separated by a 10-amino-acid spacer (H1068-H1079) located in the juxtamembrane region of c-Met function as a putative novel NLS. Deletion of these sequences significantly abolished the nuclear translocation of c-Met, as did substitution of the histidines with alanines. This substitution also decreased the association of c-Met fragment with importin beta. The putative NLS of c-Met is unique in that it relies on histidines, whose positive charge changes depending on pH, rather than the lysines or arginines, commonly found in classical bipartite NLSs, suggesting the possible 'pH-dependency' of this NLS. Indeed, decreasing the cytosolic pH either with nigericin, an Na+/H+ exchanger or pH 6.5 KRB buffer significantly increased the level of nuclear c-Met and the interaction of the c-Met fragment with importin beta, indicating that low pH itself enhanced nuclear translocation. Consistent with this, nigericin treatment also increased the nuclear level of endogenous c-Met in HeLa cells. The putative aberrant bipartite NLS of c-Met seems to be the first example of what we call a 'pH-dependent' NLS.

Association of expression of HGF and its receptor c-Met to primary colorectal cancers with synchronous liver metastasis / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the association between expression of hepatocyte growth factor(HGF) and its receptor c-Met and primary colorectal cancers with synchronous liver metastases.</p><p><b>METHODS</b>A total of 30 colorectal cancer patients with synchronous liver metastasis underwent radical resection of primary cancer and liver cancer in our hospital from June 2001 to June 2010. According to lymphatic metastasis, patients were divided into group A(T1~T4N1~N2M1, n=21) and group B(T1~T4N0M1, n=9). Twenty-one matched T1~T4N1~N2M0 and 21 T1~T4N0M0 patients were used as the controls of group A. Nine matched T1~T4N0M0 patients were used as the controls of group B. Expressions of HGF and c-Met in tissues of primary loci, liver loci and metastatic loci were detected by immunohistochemistry.</p><p><b>RESULTS</b>In primary loci of group A, the positive rate of HGF was significantly higher than that of T1~T4N1~N2M0 and T1~T4N0M0 controls [71%(15/21) vs. 43%(9/21), 19%(4/21), all P<0.05]. The positive rate of c-MET[90%(19/21)] was significantly higher compared to T1~T4N0M0 control[43%(9/21), P<0.05], while not significantly different compared to T1~T4N1~N2M0 control[86%(18/21)]. In primary loci of group B, positive rates of HGF and c-MET were not significantly different as compared to T1~T4N0M0 control[6/9 vs. 5/9, P>0.05; 8/9 vs. 6/9, P>0.05]. Concordance of HGF and c-MET expression in group A among primary loci, lymphatic metastatic loci and hepatic metastatic loci was 81%(17/21) and 76%(16/21).</p><p><b>CONCLUSION</b>HGF-c-Met may play a role in colorectal cancer patients with synchronous liver metastasis who have regional lymphatic metastasis, and may have few effect on colorectal cancer with synchronous liver metastasis without corresponding lymphatic metastasis.</p>