肝细胞生长因子及其受体c-Met在肾细胞癌组织中的表达

目的　探讨肝细胞生长因子 (HGF)及其受体c Met在肾细胞癌中表达的临床意义。方法　应用Northernblot方法检测 2 6例肾细胞癌和 10例非癌症肾组织HGFmRNA和c MetmRNA的表达情况。同时以GAPDH作为内参照。结果　 2 6例肾癌标本中 ,HGFmRNA及c MetmRNA表达均为阳性者 2 1例 ,占 80 .8%。临床病期分析结果显示 ,肾癌组织中TNM分期越高 ,HGFmRNA和c MetmRNA的表达越强烈 ,而且c MetmRNA表达量高于HGFmRNA。但对照组中的HGFmRNA和c MetmRNA均只有弱表达。结论　HGFmRNA及其受体c MetmRNA在肾细胞癌的生长、浸润和转移过程中可能起重要作用 ,对肾脏恶性肿瘤的诊断和预后的判定 ,可能具有潜在的临床价值     

肝细胞生长因子受体原癌基因c-Met mRNA在鼻咽癌中的表达及意义

Objective： To explore the expression of c-Met mRNA in nasopharyngeal carcinomas （NPC） and its relation with clinical biological behavior. Methods： In situ hybridisation was used to detect mRNA expression of c-Met in 15 cases of non-tumor nasopharyngeal （NP）, 55 cases of NPC. Results： The positive rates of c-Met mRNA in NP and NPC cells were 13.3% （2/15） and 61.8% （34/55） respectively. The expression of c-Met mRNA was significantly correlated with lymph node metastasis, local invasion （skull base erosion）, and clinical stage. In cases with cervical lymph node metastasis, local invasion, and clinical stage III and IV （UICC）, the positive rates of expression of c-Met mRNA were significantly higher than that in those without the conditions mentioned above （P 〈 0.05 or P 〈 0.01）. But it was not significantly correlated with age, gender, histologic grade, and cranial nerve palsy （P 〉 0.05）. Conclusion： The abnormal expression of c-Met gene was well correlated with the biological behavior of metastasis and invasion. To detection the expression of c-Met mRNA could serve as an important index to estimate the prognosis of NPC. C-Met may be a new diagnostic/therapeutic target of NPC.     

The prolyl isomerase Pin1 is overexpressed in human esophageal cancer

Peptidyl-prolyl isomerase Pin1 specifically catalyzes the cis/trans-isomerization of proline in the target sequence of phosphorylated Ser/Thr-Pro in over 50 critical regulatory proteins. Pin1 is abnormally overexpressed in a range of human cancers, including lung, breast, colon and prostate cancers. However, few reports of Pin1 overexpression are currently available in clinical samples. Therefore, we examined the expression of Pin1 and p53 in non-pathological human tissues and esophageal cancer tissues. In esophageal cancer tissues, Pin1 and p53 immunoreactivity was detected in cancer cells in 67 and 58% of cases, respectively. Moreover, Pin1 and p53 immunoreactivity was significantly correlated with lymph node-positive disease and more advanced cancer stage. The results demonstrated that high expression levels of Pin1 correlated with high levels of p53. Therefore, Pin1 is suggested to play key roles in the regulation of esophageal cancer.     

CIP2A is overexpressed in esophageal squamous cell carcinoma

A human oncoprotein-designed cancerous inhibitor of PP2A (CIP2A) has been recently identified, which can stabilize c-Myc protein by inhibiting its degradation mediated by protein phosphatase 2A (PP2A) in tumor cells and promote the proliferation of various cancer cells. Esophageal squamous cell carcinoma (ESCC) is a highly aggressive cancer with poor prognosis worldwide. However, the underlying molecular mechanism of the development of ESCC is still poorly understood. In the present study, the CIP2A expression between normal and malignant esophageal tissues was compared by immunohistochemical analysis; moreover, the mechanisms of CIP2A-mediated tumorigenesis were investigated by evaluating its role in cell proliferation, cell cycle, apoptosis and senescence. We found that the positive staining of CIP2A was found in 36 of 40 (90%) of cancer tissues, whereas only 8 of 40 (20%) normal esophageal mucosa exhibited positive CIP2A staining. The CIP2A is significantly overexpressed in human esophageal tumors when compared with normal tissues (χ² = 39.6, P < 0.01). On the other hand, the CIP2A expression was not associated with age, gender, tumor burden, or differentiation status. Depletion of CIP2A expression led to impaired clonogenicity and senescence, which is the primary mechanism of CIP2A in oncogenesis. Therefore, CIP2A may be a candidate in diagnosis and therapy of esophageal cancer.     

小鼠肾发育过程中肝细胞生长因子及其受体的表达

目的观察肝细胞生长因子（hepatocyte growth factor,HGF）及其受体（c-Met）在小鼠肾发育中的时空性表达,探讨其与肾发育的关系。方法采用免疫组织化学技术结合体视学方法对不同胚龄及生后日龄小鼠肾组织HGF和c-Met的表达及其含量变化进行系统观察和定量分析。结果HGF和c-Met在各期的肾小体、皮质肾小管及集合管均有表达,且随胚（日）龄增加在各期肾小体、皮质肾小管及集合管的表达是先增后减。结论推测HGF和c-Met可能对肾各结构的发育以及成熟肾的形态维持起重要作用。     

The Axl receptor tyrosine kinase is an adverse prognostic factor and a therapeutic target in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) arises in the backdrop of reflux-induced metaplastic phenomenon known as Barrett esophagus. The prognosis of advanced EAC is dismal, and there is an urgent need for identifying molecular targets for therapy. Serial Analysis of Gene Expression (SAGE) was performed on metachronous mucosal biopsies from a patient who underwent progression to EAC during endoscopic surveillance. SAGE confirmed significant upregulation of Axl “tags” during the multistep progression of Barrett esophagus to EAC. In a cohort of 92 surgically resected EACs, Axl overexpression was associated with shortened median survival on both univariate (p < 0.004) and multivariate (p < 0.036) analysis. Genetic knockdown of Axl receptor tyrosine kinase (RTK) function was enabled in two EAC lines (OE33 and JH-EsoAd1) using lentiviral short hairpin RNA (shRNA). Genetic knockdown of Axl in EAC cell lines inhibited invasion, migration and in vivo engraftment, which was accompanied by downregulation in the activity of the Ral GTPase proteins (RalA and RalB). Restoration of Ral activation rescued the transformed phenotype of EAC cell lines, suggesting a novel effector mechanism for Axl in cancer cells. Pharmacological inhibition of Axl was enabled using a small molecule antagonist, R428 (Rigel Pharmaceuticals). Pharmacological inhibition of Axl with R428 in EAC cell lines significantly reduced anchorageindependent growth, invasion and migration. Blockade of Axl function abrogated phosphorylation of ERBB2 (Her-2/neu) at the Tyr877 residue, indicative of receptor crosstalk. Axl RTK is an adverse prognostic factor in EAC. The availability of small molecule inhibitors of Axl function provides a tractable strategy for molecular therapy of established EAC.Key words: Barrett esophagus, Axl, Ral GTP, SAGE     

HGF、c-Met和VEGF-C在宫颈癌中的表达

 目的检测宫颈癌组织中HGF及其受体原癌基因c-Met和VEGF-C的分子表达水平及三者间的关系。方法 采用实时荧光定量RT-PCR(Real Time fluorescence Quantitative PCR,FQ RT-PCR)技术相对定量检测43 例宫颈浸润癌,30例CIN Ⅲ和27例正常宫颈组织标本中HGF mRNA、c-Met mRNA和VEGF-C mRNA的表达水平 。结果HGF mRNA、c-Met mRNA和VEGF-C mRNA在正常宫颈、CIN Ⅲ和宫颈浸润癌组织中的表达水平依次升 高,差异有统计学意义(P<0.05)。宫颈癌组织中三者表达水平与肿瘤临床分期、肿瘤直径大小、浸润深度 、淋巴结转移有关(P均<0.05)。 HGF mRNA与c-Met mRNA和VEGF-C mRNA表达相关(P<0.01)。结论HGF、c- Met和VEGF-C在宫颈癌发生、发展、转移中发挥重要作用,它们参与了宫颈癌新生血管和淋巴管的形成, 对宫颈癌的诊断、治疗及预后有指导意义。     

HGF/c-Met pathway is one of the mediators of sunitinib-induced tumor cell type-dependent metastasis

Recent studies in several tumor models indicated that treatment with angiogenic inhibitors may trigger induction of metastasis to other organs. Here we investigated modes of resistance and invasion in several tumor cell lines including 4T1 (breast), H460 (lung) and Colo205 (colorectal) using sunitinib at doses comparable to clinically utilized regimen. In comparison with vehicle-treated tumors, sunitinib increased metastasis to lung in 4T1 tumors and to peritoneal lymph node in Colo205 tumors. However, the same treatment did not induce invasiveness in H460 tumors, further suggesting that accelerating metastasis during treatment with angiogenic inhibitors is tumor cell-type dependent. Interestingly, Crizotinib (a dual inhibitor of c-Met and ALK pathways) as single agent or in combination with sunitinib reduced metastasis in all models tested suggesting a role for c-Met/HGF pathway in intrinsic- or sunitinib-induced-metastasis. Moreover, ELISA data showed that while c-Met is highly enriched in tumor cells, HGF is secreted mainly by the stroma (mouse HGF) suggesting a paracrine fashion for c-Met pathway activation in the tumors. In conclusion, our findings indicate that sunitinib-induced metastasis is tumor cell-type dependent and further supports a rationale for combination of anti-angiogenics and c-Met inhibition in the clinic.     

Constitutive activation of c-Met is correlated with c-Met overexpression and dependent on cell-matrix adhesion in lung adenocarcinoma cell lines

In this study we explored the mechanisms of constitutive activation of c-Met in lung adenocarcinoma cell lines. First, we examined levels of c-Met and phospho-c-Met (Y1234/Y1235) in a panel of lung adenocarcinoma cell lines by Western blot analysis. c-Met expression was found in 12 of 14 cell lines and an overall correlation between the expressions of c-Met and phospho-c-Met was noted. c-Met was constitutively activated particularly at high levels in five cell lines (PC3, LC-2/ad, L27, H1648, and H2009). c-Met amplification was identified in L27 and H1648 by single nucleotide polymorphism array analysis, but no mutations were identified in the Sema domain or in any part of the cytoplasmic domain of c-Met. Experiments with neutralizing anti-hepatocyte growth factor (HGF) antibody, scatter assay using Madin–Darby canine kidney cells, and Western blotting on conditioned media of the cell lines revealed that the constitutive phosphorylation of c-Met was largely ligand-independent. The inhibition of cell–matrix adhesion induced the dephosphorylation of c-Met in the five cell lines tested. This was accompanied by downregulation of c-Met in three of the five cell lines. In contrast, the inhibition of cell–cell adhesion by neutralizing E-cadherin antibody had a minimal effect on the expression and phosphorylation of c-Met. These results reveal three features of the constitutive activation of c-Met in our panel of lung adenocarcinoma cell lines: (i) it correlates with c-Met overexpression, either with or without gene amplification; (ii) it is largely ligand-independent; and (iii) it depends on cell–matrix adhesion. ( Cancer Sci 2008; 99: 14–22)     

HGF/c-Met在肝细胞癌中作用的研究进展

肝细胞癌是世界上最具破坏力的癌症之一,其主要治疗方式为手术治疗,但大部分患者确诊时已失去手术机会,仅部分患者可行手术治疗,且术后的转移率及复发率较高,近期相关研究发现,肝细胞生长因子(HGF)/间充质-上皮转换受体(c-Met)轴的异常激活与HCC的转移潜力及预后不良相关,为肝细胞癌的靶向治疗提供新方向。目前针对HGF/c-Met信号传导途径的有效治疗药物仍处于研究重点,现就HGF/c-Met通路在肝细胞癌中的研究进展进行综述。     

Radiation stimulates HGF receptor/c-Met expression that leads to amplifying cellular response to HGF stimulation via upregulated receptor tyrosine phosphorylation and MAP kinase activity in pancreatic cancer cells

Hepatocyte growth factor (HGF) is a stromal-derived cytokine that plays a crucial role in invasion and metastasis of tumor cells through the interaction with HGF receptor, c-Met, which is frequently overexpressed in pancreatic cancer. The present study was designed to investigate the change in HGF receptor and HGF-mediated signaling after irradiation in pancreatic cancer cells. Six cell lines from human pancreatic cancer were included in the study. Gamma-radiation was used for irradiation treatment. The changes in expression levels of c-Met were evaluated by immunoblot and confirmed morphologically by indirect immunofluorescence staining. Whether the resultant alteration in c-Met would cascade as biologically usable signals upon HGF ligation was traced by receptor tyrosine phosphorylation analysis and mitogen activated protein kinase (MAP kinase or MAPK) activity assay. The various biological responses to HGF (including cell proliferation, cell scattering, migration and invasion) were evaluated as well. We also used a 4-kringle antagonist of HGF, NK4, to block the HGF/c-Met signaling pathway. Both immunoblot and immunofluorescent analysis showed moderate increased expression of c-Met in 3 of 6 pancreatic cancer cell lines after irradiation. The actions seemed to be dose-responsible, which began at 3 hr and reached its peak value at 24 hr following irradiation. The radiation-increased expression of c-Met could transform into magnifying receptor tyrosine phosphorylation reaction and MAP kinase activity once the ligand was added, fairly corresponding with alteration in the receptor. Sequentially, the cellular responses to HGF, including scattering and invasion but not proliferation, were enhanced. Also, in the presence of HGF, the elevated receptor could help to recover the radiation-compromised cell migration. A recombinant HGF antagonist, NK4 could effectively block these aberrant effects activated by irradiation both in molecular and cellular levels, thus suggesting the deep involvement of the c-Met/HGF pathway in the enhanced malignant potential after irradiation. These results suggest that radiation may promote HGF-induced malignant biological behaviors of certain pancreatic cancer cells through the up-regulated HGF/c-Met signal pathway. Selectively targeted blockade of the HGF/c-Met pathway could help to abolish the enforced malignant behavior of tumor cells by irradiation and therefore may improve the efficacy of radiotherapy for pancreatic cancer.     

Immunohistochemical expression of hepatocyte growth factor and c-Met/HGF receptor in benign and malignant human prostate tissue

Hepatocyte growth factor (HGF) has been proposed to be an autocrine/paracrine growth factor for carcinomas of various organs. We recently demonstrated that HGF produced by prostate-derived stromal cells was a paracrine growth factor that stimulated the growth of androgen-independent prostate cancer cells in vitro and in vivo. To assess possible involvement of HGF in prostate cancer, we examined the immunohistochemical expression and localization of HGF and c-Met/HGF receptor in benign and malignant human prostate tissues. In benign glands, columnar cells generally were negative for c-Met, but basal cells were stained uniformly at a high level. In high-grade prostatic intraepithelial neoplasia (PIN) and carcinoma, more than 50% of these foci were stained uniformly. There was no difference in the frequency of positively stained cells by Gleason score. The prostate stroma stained diffusely for HGF, and the staining intensity varied depending upon the amounts of smooth-muscle cells that were stained more intensely than the connective-tissue matrix. A great majority of benign columnar cells were negative for HGF whereas high-grade PIN and carcinoma foci stained focally for HGF. Hormonal ablation therapy prior to prostatectomy did not seem to alter the expression of HGF/c-Met in carcinoma cells. These results indicate that, as the degree of neoplasia progresses, epithelial cells begin to express c-Met protein, that PIN and carcinoma may have developed a c-Met-HGF paracrine loop with the stroma, and that in some carcinoma foci an autocrine loop may operate with HGF expressed by carcinoma cells themselves.     

胃癌组织中HGF、c-Met的表达及意义

 目的 探讨HGF和c-Met的表达与胃癌临床病理生物学行为的关系以及它们之间的相关性。 方法 应用免疫组化方法检测52例胃癌患者癌组织中HGF、c-Met的表达。 结果 HGF的表达与组织学分级、浸润深度、临床分期、淋巴结转移显著相关（P＜0.05）,与年龄、肿瘤大小无关（P＞0.05）。c-Met的表达与组织学分级及淋巴结转移密切相关,而与肿瘤大小、年龄、浸润深度、临床分期无关（P＞0.05）。且两者表达呈正相关（r=0.342,P＜0.05）。 结论 HGF及c-Met促进了胃癌组织的生长与转移,具有协同作用,可作为胃癌的预后评估因子。     

Neuromedin U is overexpressed in pancreatic cancer and increases invasiveness via the hepatocyte growth factor c-Met pathway

Neuromedin U (NmU) is a bioactive peptide, ubiquitously expressed in the gastrointestinal tract. Here, we analyzed the role of NmU in pancreatic ductal adenocarcinoma (PDAC) pathogenesis. NmU and NmU receptor-2 mRNA were significantly overexpressed in PDAC and in metastatic tissues. NmU and NmU receptor-2 were localized predominantly in cancer cells. NmU serum levels decreased after tumor resection. Although NmU exerted no effects on cancer cell proliferation, it induced c-Met and a trend towards increased invasiveness as well as an increased hepatocyte growth factor (HGF)-mediated scattering. Thus, NmU may be involved in the HGF-c-Met paracrine loop regulating cell migration, invasiveness and dissemination of PDAC.     

EphA4 receptor, overexpressed in pancreatic ductal adenocarcinoma, promotes cancer cell growth

To isolate novel diagnostic markers and drug targets for pancreatic ductal adenocarcinoma (PDAC), we previously performed expression profile analysis of PDAC cells using a genome-wide cDNA microarray combined with laser microdissection. Among dozens of up-regulated genes identified in PDAC cells, we herein focused on one tyrosine kinase receptor, Eph receptor A4 (EphA4), as a molecular target for PDAC therapy. Immunohistochemical analysis validated EphA4 overexpression in approximately half of the PDAC tissues. To investigate its biological function in PDAC cells, we knocked down EphA4 expression by siRNA, which drastically attenuated PDAC cell viability. In concordance with the siRNA experiment, PDAC-derivative cells that were designed to constitutively express exogenous EphA4 showed a more rapid growth rate than cells transfected with mock vector, suggesting a growth-promoting effect of EphA4 on PDAC cells. Furthermore, the expression analysis for ephrin ligand family members indicated the coexistence of ephrinA3 ligand in PDAC cells with EphA4 receptor, and knockdown of ephrinA3 by siRNA also attenuated PDAC cell viability. These results suggest that the EphA4-ephrinA3 pathway is likely to be a promising molecular target for pancreatic cancer therapy.     

HGF/c-Met acts as an alternative angiogenic pathway in sunitinib-resistant tumors

Molecular and cellular mechanisms underlying resistance/low responsiveness to antiangiogenic compounds are under extensive investigations. Both populations of tumor and stroma (nontumor compartment) seem to contribute in inherent/acquired resistance to antiangiogenic therapy. Here, investigating in vivo efficacy of sunitinib in experimental models resulted in the identification of tumors that were resistant/sensitive to the therapy. Analysis of tumor protein lysates indicated a greater concentration of hepatocyte growth factor (HGF) in resistant tumors than in sensitive ones. In addition, using flow cytometry, c-Met expression was found to be significantly higher in endothelial cells than in tumor cells, suggesting that HGF might target the vascular endothelial cells in resistant tumors. Combination of sunitinib and a selective c-Met inhibitor significantly inhibited tumor growth compared with sunitinib or c-Met inhibitor alone in resistant tumors. Histology and in vitro analyses suggested that combination treatment mainly targeted the vasculature in the resistant tumors. Conversely, systemic injection of HGF in the sensitive tumor models conferred resistance to sunitinib through maintenance of tumor angiogenesis. In conclusion, our study indicates a role for HGF/c-Met pathway in development of resistance to antiangiogenic therapy and suggests a potential strategy to circumvent resistance to vascular endothelial growth factor receptor tyrosine kinase inhibitor in the clinic.     

FXYD3 is overexpressed in pancreatic ductal adenocarcinoma and influences pancreatic cancer cell growth

The expression and localization of FXYD domain containing ion transport regulator 3 (FXYD3), a transmembrane protein that acts as a chloride channel or chloride channel regulator, was analyzed in pancreatic tissues derived from donors and patients suffering from chronic pancreatitis (CP) or pancreatic ductal adenocarcinoma (PDAC) as well as in pancreatic cancer cells using QRT-PCR, laser-capture microdissection and microarray analysis, in situ hybridization and immunohistochemistry. FXYD3 antisense expressing T3M4 pancreatic cancer cells were generated and compared to control cells using anchorage-dependent and independent growth assays, and xenotransplantation into nude mice. FXYD3 mRNA levels were 3.4-fold increased in PDAC tissues compared to donor specimens (p = 0.006), and 3.9-fold increased in microdissected cancer cells compared to normal pancreatic ductal cells (p = 0.02). FXYD3 was localized in the tubular complexes and PanIN lesions of both CP and PDAC, as well as in pancreatic cancer cells. Downregulation of FXYD3 by stable antisense transfection increased significantly the doubling time of T3M4 pancreatic cancer cells from 44 +/- 2 hr to 55 +/- 12 hr (p = 0.02). Nude mice transplanted with antisense transfected cells displayed a significant increase in tumor doubling time from 3.3 days +/- 1.0 to 4.3 days +/- 0.43 (p = 0.058). Anchorage-independent growth and sensitivity to 5-fluorouracil, gemcitabine and cisplatin as well as to MgCl(2) were not dependent on the level of FXYD3 expression. In conclusion, overexpression of FXYD3 in pancreatic cancer may contribute to the proliferative activity of this malignancy.     

Stomatin-like protein 2 is overexpressed and related to cell growth in human endometrial adenocarcinoma

Stomatin-like protein 2 (SLP-2) is a novel and unusual stomatin homologue of unknown functions. It was first identified to be overexpressed and involved in regulating cell growth and cell adhesion in human esophageal squamous cell carcinoma. We show herein the involvement of SLP-2 in human endometrial adenocarcinoma, and the effects of SLP-2 on endometrial adenocarcinoma cell growth. The expression of SLP-2 was evaluated in human endometrial adenocarcinoma by semi-quantitative RT-PCR, Westernblotting and immunohistochemistry. Sense and antisense SLP-2 eukaryotic expression plasmids were transfected into the human endometrial adenocarcinoma cell line HEC-1B. MTT assay and flow cytometry assay were performed to investigate the roles of the SLP-2 gene. SLP-2 was overexpressed in endometrial adenocarcinoma compared with their normal counterparts (P相似文献