肝细胞生长因子受体—原癌基因c-Met蛋白

本文概述了肝细胞生长因子(HGF)受体——原癌基因c-met编码蛋白的结构,信号转导途径与基因表达调控等方面的进展。     

肝细胞生长因子与急性肾衰竭

肝细胞生长因子 (HGF)是一种高效的多效性因子 ,对多种器官的不同类型细胞均有多种生物学作用。HGF对于肾脏的发生、形成、修复及肾脏病理过程有重要作用 ,在急性肾衰竭 (ARF)时HGF具有促进肾小管修复及肾脏再生 ,降低死亡率 ,缩短病程的作用 ;在各种慢性肾脏疾病的发生发展中具有重要的调节作用。     

肝细胞生长因子研究进展

查阅近二十年国外有关HGF/SF文献,基本弄清了HGF/SF的分子结构及组织分布,说明了HGF/SF的调节和cmet受体及两者的关系,揭示了HGF/SF的生物活性、HGF/SF和肿瘤扩散以及与肝再生的关系.因此,HGF/SF在肝再生中起主要作用;是肾再生的关键因子;可促进伤口愈合;通过增加恶性细胞的侵袭性,HGF/SF可能作为肿瘤转移的重要因素之一.     

肝细胞生长因子研究进展

肝细胞生长因子是一个多效应生长因子 ,参与机体多种器官组织细胞的生长、再生和重塑过程。本文综述近年来对 HGF在生物学方面的研究 ,包括 HGF/c- m et受体的生化、结构、基因表达和信号分子转导等方面     

肝细胞生长因子/c-Met系统在鼻咽癌中的表达及意义

目的　探讨肝细胞生长因子(HGF)及其受体c- Met蛋白在鼻咽癌组织中的表达水平,研究HGF/c- Met系统对鼻咽癌细胞侵袭转移的影响。方法　收集1999—2003年期间45例确诊的鼻咽原发癌活检组织标本,采用免疫组织化学(LSAB)法检测鼻咽癌组织中HGF α亚单位和c- Met的表达,并与患者的病理及临床资料相联系。采用流式细胞术检测鼻咽癌细胞株CNE- 2在HGF刺激前后c- Met阳性癌细胞百分率的改变;蛋白印迹法和逆转录PCR法分别用于检测癌细胞株c -Met蛋白表达和mRNA表达的变化。结果　在45例鼻咽原发癌组织中,癌细胞c- Met的阳性表达率为91. 1% (41 /45),但仅有1例鼻咽癌细胞表达HGF( 2 .2%, 1 /45 )。HGF主要在鼻咽癌间质中的淋巴细胞表达。癌细胞c Met的表达水平与淋巴结转移有关(P=0 .024 ),且与淋巴细胞表达HGF呈正相关(rs=0 .450,P=0 .002)。癌细胞c Met表达量在间质淋巴细胞高表达HGF的病例中明显高于淋巴细胞低表达HGF的癌组织(P=0 .009)。但癌细胞c Met的表达与患者性别、年龄、病理组织学分型以及临床分期均未显示相关性。鼻咽癌细胞株CNE 2在HGF诱导24h后,c Met阳性的癌细胞比例即有明显增加,由(46 .6±9 .02)%增加至(85. 8±6. 05)% (P=0 .003 ),癌细胞c Met蛋白表达相对强度和mRNA表达水平均有显著提高,     

肝细胞生长因子在缺血性疾病的研究及进展

肝细胞生长因子(hepatocyte growth factor,HGF)是一类具有多功能生物活性的生长因子,参与机体多种组织器官及细胞的生长、再生、重塑、促血管新生等过程。因其具有生物活性的多样性,被广泛用于基础实验及临床研究,然而其对血管内皮细胞的增生及维护内皮细胞功能从而促进血管新生加速其侧枝循环作用,被广泛用于缺血性疾病的研究,本文就近年来HGF在缺血性疾病等方面进行综述。     

肝细胞生长因子受体在小鼠肾发育中的表达

目的:观察肝细胞生长因子受体(c-Met)在小鼠肾发育中的时空性表达,探讨c-Met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和免疫印迹法,测定不同胚龄(E)11、14、16d和18d及生后日龄(P)1、3、7、14、21d和40d小鼠肾组织内c-Met的表达及其含量变化.结果:免疫组织化学结果显示c-Met的表达在各期集合管较强,皮质肾小管内次之,肾小体表达较弱.体视学测量和免疫印迹法结果均显示随着胚日龄的增加,c-Met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: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.     

肝细胞生长因子生物学作用研究进展

肝细胞生长因子作用于多种类型的细胞,具有多样的生物学作用。它可刺激细胞增殖,修复组织器官的损伤,发挥有丝分裂原的作用;它可促进胚胎的发育及各类组织器官的形态发生,发挥形态发生原的作用;它还可促进细胞的迁移和侵袭,对某些组织的形成和发育及肿瘤的转移、侵袭具有重要意义。     

肝细胞生长因子激活物抑制剂1基因在前列腺癌组织中的表达及其与肿瘤血管生成的关系

目的 探讨肝细胞生长因子激活物抑制剂1(HAI-1)在前列腺癌中的表达及其与肿瘤血管生成的关系.方法 应用半定量RT-PCR法检测HAI-1基因在48例前列腺癌组织和20例前列腺增生组织中的表达水平;采用免疫组化SP法测定上述组织CD34的表达,并进行微血管密度(MVD)计数.分析HAI-1基因表达与前列腺癌临床病理指标及MVD的关系.结果 20例前列腺增生组织中,HAI-1的阳性率为85.00％,而48例前列腺癌组织的阳性率为52.08％,差异有统计学意义(P＜0.05).前列腺癌A+B期HAI-1的阳性率(71.43％)显著高于C+D期(37.04％,P＜0.05).前列腺癌组织中HAI-1基因的表达与MVD计数之间呈负相关(r=-0.647,P＜0.05).结论 HAI -1基因的表达缺失可能与前列腺癌的发生发展、浸润转移存在一定的关系.     

肝细胞生长因子结构和功能研究进展

肝细胞生长因子是一种能够促进肝细胞分裂增殖的多效性细胞因子 .它是由一条重链和一条轻链组成的异二聚体 ,其中重链由 N端和 4个 Kringle区组成。目前 ,NK1的晶体结构已经解出 ,在 N端有肝素糖蛋白结合区 ,HGF分子与肝素糖蛋白的相互作用对 HGF分子二聚化和内吞清除都有重要意义。 Kringle区的空间取向对HGF分子与受体结合非常重要 ,其中 K1、K2发挥重要作用 ,而 K3、K4发挥辅助作用。轻链有促进受体酪氨酸磷酸化的作用     

HGF/c-Met信号通路在克唑替尼诱导不同肺癌细胞株凋亡中的作用

 目的: 观察克唑替尼(crizotinib)诱导不同肺癌细胞株凋亡中HGF/c-Met信号通路的变化并探讨其调控机制。方法: 采用噻唑蓝(MTT)法检测克唑替尼对H1993(c-Met扩增的肺腺癌细胞)、H2228(含有EML4-ALK融合基因的肺癌细胞)和A549细胞的活力抑制情况;采用流式细胞术检测3种细胞在克唑替尼作用后24 h、48 h和72 h的凋亡率;采用Western blot检测细胞在克唑替尼作用前后HGF/c-Met信号通路中MET蛋白及其磷酸化形式p-MET的水平,同时观察其下游通路关键蛋白AKT、ERK、p-AKT和p-ERK的变化情况。结果: MTT结果表明克唑替尼作用72 h后,H1993、H2228和A549细胞株的细胞活力抑制率均呈剂量依赖性升高。流式细胞术检测发现随着克唑替尼作用时间的延长,细胞凋亡率呈时间依赖性增加(P<0.05)。Western blot检测结果提示在H1993细胞株和H2228细胞株中,p-MET、p-AKT和p-ERK随着时间的延长蛋白水平呈现下降趋势。而在A549细胞株中p-AKT、p-ERK和p-MET在药物作用72 h后的变化趋势不明显。结论: 初步证实HGF/c-Met信号通路与克唑替尼诱导肺癌细胞株H1993和H2228凋亡相关。     

Hepatocyte growth factor (HGF) downregulates thrombospondin 1 (TSP-1) expression in thyroid papillary carcinoma cells

This study investigates the expression of thrombospondin-1 in papillary carcinoma of the thyroid and the role of Met-HGF interaction in TSP-1 regulation. In tissue sections, immunostaining for TSP-1 was associated with the fibrous tumour stroma, and showed areas of marked intensity adjacent to the basal membrane of tumour cells. Investigation of TSP-1 RNA expression showed that, in 10 of 14 cases, TSP-1 mRNA levels were significantly lower in tumour tissue (20-100% reduction; mean = 55% +/- 20; p = 0.001) than in the corresponding normal thyroid. Since it has been reported that HGF can downregulate the expression of TSP-1 mRNA, TSP-1 mRNA levels were measured in 7 primary cultures, established from thyroid papillary carcinomas (TPC), and in 1 TPC cell line prior to, or after, stimulation with HGF. A marked decrease in TSP-1 mRNA levels was observed after HGF stimulation in 6/7 primary cultures (60-100% decrease (mean = 79 +/- 15%; p = 0.006) and in the TPC cell line; moreover, the decrease in TSP-1 mRNA in cell extracts was associated with a decrease in TSP-1 protein in culture supernatants. The HGF activity was dose dependent and the downregulation lasted for at least 48 h after stimulation. The high-level expression of Met protein, the high-affinity receptor for HGF, in most cases of papillary carcinoma of the thyroid is consistent with the possibility that HGF-Met interaction plays a crucial role in regulating the expression of TSP-1 in this tumour type.     

Disease-dependent reciprocal phosphorylation of serine and tyrosine residues of c-Met/HGF receptor contributes disease retardation of a transgenic mouse model of ALS

Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by progressive degeneration of motoneurons. We have demonstrated that hepatocyte growth factor (HGF) attenuates loss of both spinal and brainstem motoneurons of ALS model mice expressing mutated human SOD1^G93A (G93A). This study was designed to assess disease-dependent regulatory mechanisms of c-Met/HGF receptor (c-Met) activation in the facial motoneurons of G93A mice. Using double transgenic mice expressing HGF and mutated SOD1^G93A (G93A/HGF), we showed that phosphorylation of c-Met tyrosine residues at positions 1230, 1234 and 1235 (phospho-Tyr), and thereby its activation, was slightly evident in G93A and highly obvious in G93A/HGF mice (but absent in WT and HGF-Tg mice). Phosphorylation of the c-Met serine residue at position 985 (phospho-Ser), a residue involved in the negative regulation of its activation, was evident in WT and HGF-Tg mice. Protein phosphatase 2A (PP2A), which is capable of dephosphorylating c-Met phospho-serine, is upregulated in the facial motoneurons of G93A and G93A/HGF mice compared with WT and HGF-Tg mice. Thus, c-Met activation is reciprocally regulated by phosphorylation between c-Met serine and tyrosine residues through PP2A induction in the presence or absence of mutant SOD1 expression, and HGF functions more efficiently in ALS and ALS-related diseases.     

Coexpression of HGF and c-Met/HGF receptor in human bone and soft tissue tumors

To understand the interaction between hepatocyte growth factor (HGF) and its receptor c-Met on various bone and soft tissue tumors, their expressions were investigated by western blot analysts, immunohistochemistry and enzyme immunoassay. Western blot analysis revealed that c-Met protein was expressed in 21 (38.8%) of 54 tumors, which detailed to seven (25.9%) of 27 bone tumors and 14 (51.8%) of 27 soft tissue tumors. Most malignant fibrous histiocy-tomas (MFH) and all neurofibromas expressed c-Met protein. The highest expression of c-Met protein was seen in a case of biphasic synovial sarcoma, where its immunoreac-tivity was localized only on the epithelial component and not on the sarcomatous component. By enzyme immunoassay for HGF, all but one MFH showed HGF production and the mean level of HGF was the highest among the tumors investigated. Neurofibmmas and osteosarcomas had the next highest mean levels of HGF production, respectively. Coexpression of HGF and c-Met was obsewed in 19 (35.2%) of 54 tumors and was frequently observed in neurofibroma, followed by MFH and synovial sarcoma. Although the mode of interaction between HGF and c-Met varies among the various bone and soft tissue tumors including MFH, their signaling system may play an Important role in the development and progression of bone and soft tissue tumors.     

Coexpression of hepatocyte growth factor and c-Met proto-oncogene product in synovial sarcoma

Hepatocyte growth factor (HGF) is a heterodlmeric polypep-tide growth factor that has pleiotropic roles, Including those of mitogen, motogen and morphogen. The HGF receptor Is characterized as a c-Met proto-oncogene product (c-Met), which is a heterodimeric tyrosine kinase receptor. Hepatocyte growth factor acts as a mediator between the mes-enchymal and epithelial tissues because HGF is produced by mesenchymal cells and c-Met is mainly expressed on various epithelial cells. Furthermore, the HGF/c-Met system plays an important role in embryogenesis and the regeneration of various organs. Synovial sarcoma (SS) are unique sarcoma that show epithelial differentiation, but little is known about their histogenesis. The expression of HGF and c-Met was examined by immunohlstochemlstry In SS specimens from 12 patients (six each of biphasic and monopha-sic fibrous types). lmmunohistochemical coexpression of HGF and c-Met was demonstrated in the epithelial component of five biphasic SS, while only c-Met was expressed in the epithelioid nests of three monophasic fibrous SS. The spindle cell component was negative for HGF and c-Met. In SS, positivity for epithelial markers, such as cytokeratins and epithelial membrane antigen, was diffusely observed in the epithelial component and was focally observed In spindle cells, while vlmentin was positive predominantly in the spindle cell component. The areas expressing HGF and c-Met corresponded to distinct epithelial structures; however, HGF and c-Met expression were not found in any other tumor cells expressing epithelial markers in the spindle cell component of SS. Considering the morphogenlc effect of HGF, which has been known to be one of Its most important roles, the unique immunohlstochemical localization of HGF and c-Met In SS suggests that the HGF/c-Met system may be closely related to the formatlon of epithellal (glandular) structures In biphasic SS.     

HGF/c-Met促进大鼠骨髓内皮祖细胞迁移能力

目的探讨肝细胞生长因子(HGF)及其受体c-Met对大鼠骨髓内皮祖细胞(EPCs)迁移能力的影响及其机制。方法提取、培养和鉴定大鼠骨髓EPCs;重组腺病毒载体介导c-Met基因转染EPCs,用real-time PCR、Western blot和CCK8分别检测c-Met的表达和细胞增殖;分别用0、5、10、20和50 ng/m L HGF处理Ad-c-Met-EPCs,并通过Transwell迁移系统检测Ad-c-Met-EPCs的迁移能力;选取适宜浓度的HGF处理EPCs、Ad-GFP-EPCs和Ad-c-MetEPCs,并设置PBS对照组和磷脂酰肌醇3-激酶抑制剂LY294002组(同时加入HGF和10 g/L的LY294002),通过Transwell迁移系统和Western blot分别检测各组细胞的迁移能力、Akt和P-Akt的表达。结果 1)Ad-c-Met-EPCs中c-Met基因与蛋白均为高表达(P0.05)。2)c-Met基因对EPCs的增殖无明显影响。3)HGF在0~50 ng/m L范围内呈浓度依赖性促进Ad-c-Met-EPCs迁移。4)HGF+Ad-c-Met-EPCs组的迁移能力和P-Akt的表达显著高于对照组、HGF+EPCs组、HGF+Ad-GFP-EPCs组和HGF+LY294002+Ad-c-Met-EPCs组(P0.05)。结论 HGF/c-Met能够显著提高EPCs的迁移能力;HGF/c-Met可能通过PI3K/Akt信号通路促进EPCs的迁移。     

Papillary carcinoma of the thyroid: evidence for a role for hepatocyte growth factor (HGF) in promoting tumour angiogenesis

The pattern of vascularization of papillary carcinoma was investigated in tumour sections from 31 cases and in primary cultures from 12 cases. Tumour sections were immunostained for von Willebrand Factor (vWF) to visualize blood vessels; for endothelial-specific nitric-oxide-synthase (EC-NOS), as a marker of endothelial cell activation; and for Ki-67 to evaluate endothelial cell proliferation. It was found that endothelial cells lining venous vessels located in peritumoural fibrous tissue were intensely EC-NOS-positive and occasionally Ki-67-positive. Capillary vessels of tumour papillae were not stained for Ki-67 and were weakly EC-NOS-positive. Primary cultures of papillary carcinoma cells were used as a potential source of factors active on endothelial cells. It was found that thyroid tumour cells contain RNAs for angiopoietin, vascular endothelial growth factor (VEGF), and VEGF-C; moreover, they release large amounts of VEGF into culture supernatants and exert chemotactic activity in vitro for the endothelial cell line SIEC. The ability of papillary carcinoma cells to release angiogenic factors could be stimulated in vitro. Hepatocyte growth factor (HGF; 25 ng/ml) induced a 1.2- to 5-fold increase in the amount of VEGF released by tumour cells and a 1.2- to 4.2-fold increase in the amount of chemotactic activity present in culture supernatants. Met protein, the high affinity HGF-receptor, is overexpressed in a large proportion of cases of papillary carcinoma. These findings are consistent with the possibility that HGF-Met protein interaction is one of the molecular mechanisms promoting the vascularization of papillary carcinoma of the thyroid.