组胺H4受体在胃腺癌组织中的表达及临床意义

目的：研究胃癌腺癌（gastric adenocarcinoma,GAC）中组胺H4受体的表达水平及其临床意义。方法：60例GAC组织（病例组）与配对癌旁组织（adjacent normal tissue,ANT）中应用免疫组织化学技术检测组胺H4受体的表达,应用实时荧光定量RT-PCR方法检测组胺H4受体mRNA的表达,统计分析组胺H4受体表达与临床病理特征之间的关系。结果：①胃腺癌组织中组胺H4受体蛋白的阳性表达率（11.7%）显著低于癌旁正常组织（96.7%）。②胃腺癌组织中组胺H4受体mRNA水平较癌旁组织明显降低（p〈0.001）。③组胺H4受体蛋白和mRNA表达异常和肿瘤的病理分级有相关性（p=0.0027和p=0.0011）,也与有无胃周淋巴结转移有关（p〈0.001和p=0.0049）。结论：组胺H4受体在胃腺癌组织有表达异常,表达量与病理分期相关。组胺H4受体表达异常和组胺水平紊乱可能在胃癌发生发展过程中有重要作用。     

组胺H4 受体在胃腺癌组织中的表达及临床意义

目的:研究胃癌腺癌(gastric adenocarcinoma,GAC)中组胺H4受体的表达水平及其临床意义。方法:60例GAC组织(病例组)与配对癌旁组织(adjacent normal tissue,ANT)中应用免疫组织化学技术检测组胺H4受体的表达,应用实时荧光定量RT-PCR方法检测组胺H4受体mRNA的表达,统计分析组胺H4受体表达与临床病理特征之间的关系。结果:①胃腺癌组织中组胺H4受体蛋白的阳性表达率(11.7%)显著低于癌旁正常组织(96.7%)。②胃腺癌组织中组胺H4受体mRNA水平较癌旁组织明显降低(p<0.001)。③组胺H4受体蛋白和mRNA表达异常和肿瘤的病理分级有相关性(p=0.0027和p=0.0011),也与有无胃周淋巴结转移有关(p<0.001和p=0.0049)。结论:组胺H4受体在胃腺癌组织有表达异常,表达量与病理分期相关。组胺H4受体表达异常和组胺水平紊乱可能在胃癌发生发展过程中有重要作用。     

雌激素受体p在胃腺癌中表达的研究

目的：检测雌激素受体β（ERβ）在胃组织的存在状况并研究其在人胃腺癌中的作用。方法：使用免疫组化方法,在蛋白水平对配对的原发性胃腺癌患者的癌组织及其癌旁非癌组织的ERB亚型进行检测,采用20例正常胃粘膜作为对照。结果：ERβ蛋白在部分胃腺癌及其癌旁非癌组织表达,但ERβ阳性率及表达模式不同。与配对的非癌组织相比,部分癌组织发生了ERβ表达减少或丢失,而且ERβ表达减少与低分化程度相关（P=0．041）,丢失的ERβ仅见于低分化癌。结论：ERβ可作为识别某些进展期胃腺癌发生发展的标志物,ERβ表达改变在低分化癌中更常见,也提示ERβ阳性胃腺癌可能比ERp表达丢失者预后更好;另外,在非癌组织腺上皮存在E邢的表达提示在正常胃组织中ERB很可能具有一种保护性作用。     

Snail基因及其蛋白、E-cadherin蛋白在胃癌中的表达及其临床意义

目的观察Snail mRNA及其蛋白、E-cadherin蛋白在胃癌组织中的表达及其与胃癌临床病理特征的关系,并探讨它们在胃癌发生、发展中的作用及其临床应用价值。方法收集96例手术切除胃癌标本,同时取80例癌旁组织作为对照。应用免疫组织化学S-P法检测胃癌组织、癌旁组织中snail蛋白、E-cadherin蛋白的表达;运用原位分子杂交技术检测胃癌组织、癌旁组织中Snail mRNA的表达。结果（1）Snail蛋白在胃癌组织阳性率（83.3%）显著高于癌旁组织（41.25%）（P〈0.05）;高、中分化组Snail蛋白阳性表达率显著低于低分化组（P〈0.05）;Snail蛋白的阳性表达率在乳头状腺癌、管状腺癌及低分化腺癌与黏液癌之间差异有显著性（P〈0.05）;Snail蛋白的表达与胃癌浸润深度、淋巴结转移及远处转移有关（P〈0.05）,与性别、年龄、肿瘤大小、肿瘤部位及临床分期无关（P〉0.05）;（2）胃癌组织中snail mR-NA的阳性率（76%）显著高于癌旁组织（30%）（P〈0.05）;高、中分化组Snail mRNA阳性表达率显著低于低分化组（P〈0.05）;Snail mRNA的阳性表达率在乳头状腺癌、管状腺癌及低分化腺癌与黏液癌之间差异有显著性（P〈0.05）;Snail mRNA的表达与浸润深度及淋巴结转移有关（P〈0.05）,与性别、年龄、肿瘤大小、肿瘤部位、临床分期及远处转移无关（P〉0.05）;（3）E-cadherin蛋白在胃癌组织阳性率（37.5%）显著低于癌旁组织（100%）（P〈0.05）;高、中分化组E-cadherin蛋白阳性率显著高于低分化组（P〈0.05）;E-cadherin蛋白阳性率在乳头状腺癌、管状腺癌及低分化腺癌与黏液癌之间差异有显著性（P〈0.05）;E-cadherin蛋白的表达与胃癌浸润深度、淋巴结转移、临床分期及远处转移有关（P〈0.05）,与性别、年龄、肿瘤大小、肿瘤部位均无关（P〉0.05）;（4）胃癌组织中snail mRNA和snail蛋白的表达呈正相关（r=0.594,P〈0.05）;Snail蛋白和E-cadherin蛋白的表达呈负相关（r=-0.234,P〈0.05）。结论（1）E-cadher-in蛋白低表达与Snail蛋白高表达可能是胃黏膜恶性转变以及胃癌发生浸润转移的重要生物学标志;联合检测E-cadherin蛋白与Snail蛋白对预测胃癌浸润转移有重要意义。（2）Snail蛋白可能在转录水平上调控E-cadherin蛋白的表达。     

抑癌候选基因NDRG2在甲状腺癌组织中的表达及其意义

目的:研究抑癌候选基因NDRG2在人类甲状腺癌组织及其癌旁组织中的表达情况.方法:收集30例甲状腺癌组织及其癌旁组织,提取总RNA,应用半定量RT-PCR方法检测NDRG2 mRNA的表达水平.分别提取30例组织的总蛋白,应用蛋白印迹技术检测其NDRG2的蛋白表达水平.结果:RT-PCR结果显示,30例甲状腺癌组织中,有25例NDRG2的mRNA水平明显降低,蛋白印迹结果显示,30例甲状腺癌组织中发现25例NDRG2的蛋白水平明显下降,与RT-PCR检测结果一致.结论:NDRG2在甲状腺癌组织中呈低表达,提示其可能对甲状腺癌的发生或发展有重要作用影响.     

Notch受体在胰腺癌组织中的表达及其临床意义

目的:探讨胰腺癌及癌旁组织中Notch1～4蛋白和mRNA表达及临床意义。方法:应用免疫组化方法检测40例胰腺癌组织及对应的癌旁组织石蜡标本中Notch1～4蛋白的表达情况;分析Notch1～4受体表达水平与胰腺癌临床病理特征关系;应用实时逆转录聚合酶链反应(Real-time RT PCR)检测冰冻胰腺癌组织及对应的癌旁组织手术标本中Notch1～4的mRNA表达情况。结果:免疫组化结果显示:Notch1、Notch2在胰腺癌组织中蛋白表达明显比胰腺癌旁组织低(P0.05);Notch3在胰腺癌组织中蛋白表达比胰腺癌旁组织高,但是差异无统计学意义(P0.05);Notch4在胰腺癌组织中蛋白表达比胰腺癌旁组织高(P0.05)。Notch1～4受体的表达与肿瘤分化程度和临床分期呈负相关(P0.05)。Real-time RT PCR结果显示:与胰腺癌旁组织相比,癌组织中Notch1,Notch2的mRNA相对表达水平显著下调;胰腺癌癌组织中Notch3,Notch4的mRNA相对表达水平显著上调。结论:Notch家族的Notch1～4受体在胰腺癌组织及其旁组织的蛋白和mRNA表达不同,Notch蛋白表达可以作为胰腺癌的风险预测因子。     

胃腺癌组织中GDF-15和p53表达特征及其临床意义

目的探讨胃腺癌及癌旁正常组织中生长分化因子15(growth differentiation factor-15,GDF-15)和p53表达的特征及临床意义。方法采用免疫组织化学Polink-1两步法检测91例胃癌手术标本,相应91例癌旁正常组织、64例肠化腺体及36例淋巴结转移癌组织中GDF-15和p53的表达特征,并结合临床资料分析其表达与临床病理参数的关系。结果 GDF-15在肠上皮化生腺体、胃腺癌和淋巴结转移癌组织中的阳性表达率均显著低于癌旁组织。GDF-15的阳性表达率与患者年龄、浸润深度、淋巴结转移及p TNM分期呈正相关,而与其它临床病理参数无关。p53在癌旁正常胃粘膜腺体和肠上皮化生腺体中均不表达,在胃腺癌和淋巴结转移癌组织中的过表达阳性率均高于癌旁组织和肠上皮化生腺体。p53过表达的阳性率与患者年龄、Lauren分型(肠型与弥漫型)和分化程度呈正相关,而与其它临床病理参数无关。GDF-15与p53免疫反应性在胃癌组织中呈正相关。结论 GDF-15可作为胃腺癌的胃壁浸润能力、淋巴结转移能力及临床病理分期的重要评价指标,而p53过表达可能与Lauren分型的肠型胃癌有关。尤其在老年患者中,GDF-15和p53过表达在胃腺癌的发生、进展中扮演重要角色,并起协同作用。     

原发性胃癌REG 1A mRNA的表达与临床病理特性的关系研究

本文采用RT-PCR的方法检测胃癌组织的REG 1A基因mRNA表达.并分析其与胃癌临床特征的相关性.结果显示有78%(183/235)的原发性胃癌REG ;A mRNA阳性.REG 1A mRNA在胃癌中的表达与肿瘤的浸润生长方式、印戒细胞癌及低分化胃腺癌关系密切.与REG lA mR.NA阳性的肿瘤患者相比,REG lA mRNA阴性高分化腺癌患者有更好的预后.同时REG 1A mR-NA阳性的肿瘤发生血行转移的机会要显著高于REG lA mRNA阴性肿瘤.因此REG lA mRNA的表达与胃癌浸润性生长密切相关,可能是高分化胃腺癌的一个不良预后指标.     

Staufen基因在结直肠癌组织中的表达

为研究甲基化差异相关基因Staufen在结直肠癌不同组织中的表达情况,采用RT-PCR和免疫组织化学等方法在结直肠癌病人中检测Staufen基因在腺癌、癌旁粘膜和相应远端切缘正常组织中的表达。研究发现,在mRNA水平上,远端切缘正常组织中Staufen基因的表达水平显著高于癌旁粘膜和腺癌（P<0.05）;从正常组织、癌旁粘膜到腺癌,Staufen基因的表达有降低的趋势;未发现性别、年龄、肿瘤部位（结肠/直肠）、分化程度、淋巴结转移等临床病理因素与Staufen基因的表达有关（P均>0.05）。正常组织与腺癌组织的Staufen蛋白的表达水平显著高于癌旁粘膜（P<0.05）,而正常组织与腺癌组织之间未发现有统计学差别（P>0.05）。结果表明,Staufen基因在癌旁粘膜和肿瘤中有低表达的趋势,该基因可能在结直肠癌的发生、发展中起作用。     

PTEN、HPVl6/18-E6蛋白和雌激素受体在宫颈腺癌中的表达及其临床意义

目的:探讨宫颈腺癌组织中抑癌蛋白PTEN、人乳头瘤病毒(HPV)16/18-E6蛋白和雌激素受体(ER)的表达及其临床意义.方法:采用免疫组织化学S-P法对65例宫颈腺癌组织进行PTEN、HPV16/18-E6蛋白和ER检测,对30例慢性宫颈炎组织中HPV16/18-E6蛋白和ER的表达进行检测.结果:宫颈腺癌组织细胞核中PTEN的表达显著低于癌旁宫颈腺上皮组织(P＜0.01),96%的宫颈腺癌细胞核呈低表达,而仅35%的癌旁宫颈腺上皮呈低表达(P＜0.01);HPV16/18-E6蛋白和ER在宫颈腺癌中的阳性表达率分别为32.1%与49.4%,均显著高于慢性宫颈炎组织(P＜0.01);HPVl6/18-E6蛋白和ER的表达与宫颈腺癌的病理学分级、临床分期无关,在宫颈腺癌中的表达呈正相关.结论:PTEN在宫颈腺癌的发生中起一定的作用,其抑癌作用环节可能在细胞核水平;部分宫颈腺癌的发病可能与HPV16/18-E6蛋白过度表达有关;部分宫颈腺癌可能属于激素依赖性,雌激素可能有协同人乳头瘤病毒致癌的作用.     

Direct binding of specific AUF1 isoforms to tandem zinc finger domains of tristetraprolin (TTP) family proteins

Tristetraprolin (TTP) is the prototype of a family of CCCH tandem zinc finger proteins that can bind to AU-rich elements in mRNAs and promote their decay. TTP binds to mRNA through its central tandem zinc finger domain; it then promotes mRNA deadenylation, considered to be the rate-limiting step in eukaryotic mRNA decay. We found that TTP and its related family members could bind to certain isoforms of another AU-rich element-binding protein, HNRNPD/AUF1, as well as a related protein, laAUF1. The interaction domain within AUF1p45 appeared to be a C-terminal "GY" region, and the interaction domain within TTP was the tandem zinc finger domain. Surprisingly, binding of AUF1p45 to TTP occurred even with TTP mutants that lacked RNA binding activity. In cell extracts, binding of AUF1p45 to TTP potentiated TTP binding to ARE-containing RNA probes, as determined by RNA gel shift assays; AUF1p45 did not bind to the RNA probes under these conditions. Using purified, recombinant proteins and a synthetic RNA target in FRET assays, we demonstrated that AUF1p45, but not AUF1p37, increased TTP binding affinity for RNA ～5-fold. These data suggest that certain isoforms of AUF1 can serve as "co-activators" of TTP family protein binding to RNA. The results raise interesting questions about the ability of AUF1 isoforms to regulate the mRNA binding and decay-promoting activities of TTP and its family members as well as the ability of AUF1 proteins to serve as possible physical links between TTP and other mRNA decay proteins and structures.     

Cell death inhibiting RNA (CDIR) derived from a 3'-untranslated region binds AUF1 and heat shock protein 27

Regulators of programmed cell death were previously identified using a technical knockout genetic screen. Among the elements that inhibited interferon-gamma-induced apoptosis of HeLa cells was a 441-nucleotide fragment derived from the 3'-untranslated region (UTR) of KIAA0425, a gene of unknown function. This fragment was termed cell death inhibiting RNA (CDIR). Deletion and mutation analyses of CDIR were employed to identify the features required for its anti-apoptotic activity. Single nucleotide alterations within either copy of the duplicated U-rich motif found in the CDIR sequence abolished the anti-apoptotic activity of CDIR and altered its in vitro association with a protein complex. Further analysis of the CDIR-binding complex indicated that it contained heat shock protein 27 (Hsp27) and the regulator of mRNA turnover AUF1 (heterogeneous nuclear ribonucleoprotein D). In addition, recombinant AUF1 bound directly to CDIR. Furthermore, expression of another AUF1-binding RNA element, derived from the 3'-UTR of c-myc, inhibited apoptosis. We also demonstrate that the level and the stability of p21(waf1/Cip1/sdi1) mRNA, a target of AUF1 with anti-apoptotic activity, were increased in CDIR-transfected cells. The level of mRNA and protein of Bcl-2, another anti-apoptotic gene, containing an AUF1 binding site in its 3'-UTR was also increased in CDIR-transfected cells. Our data suggest that AUF1 regulates apoptosis by altering mRNA turnover. We propose that CDIR inhibits apoptosis by acting as a competitive inhibitor of AUF1, preventing AUF1 from binding to its targets.     

Alternatively expressed domains of AU-rich element RNA-binding protein 1 (AUF1) regulate RNA-binding affinity, RNA-induced protein oligomerization, and the local conformation of bound RNA ligands

AU-rich element RNA-binding protein 1 (AUF1) binding to AU-rich elements (AREs) in the 3'-untranslated regions of mRNAs encoding many cytokines and other regulatory proteins modulates mRNA stability, thereby influencing protein expression. AUF1-mRNA association is a dynamic paradigm directed by various cellular signals, but many features of its function remain poorly described. There are four isoforms of AUF1 that result from alternative splicing of exons 2 and 7 from a common pre-mRNA. Preliminary evidence suggests that the different isoforms have varied functional characteristics, but no detailed quantitative analysis of the properties of each isoform has been reported despite their differential expression and regulation. Using purified recombinant forms of each AUF1 protein variant, we used chemical cross-linking and gel filtration chromatography to show that each exists as a dimer in solution. We then defined the association mechanisms of each AUF1 isoform for ARE-containing RNA substrates and quantified relevant binding affinities using electrophoretic mobility shift and fluorescence anisotropy assays. Although all AUF1 isoforms generated oligomeric complexes on ARE substrates by sequential dimer association, sequences encoded by exon 2 inhibited RNA-binding affinity. By contrast, the exon 7-encoded domain enhanced RNA-dependent protein oligomerization, even permitting cooperative RNA-binding activity in some contexts. Finally, fluorescence resonance energy transfer-based assays showed that the different AUF1 isoforms remodel bound RNA substrates into divergent structures as a function of protein:RNA stoichiometry. Together, these data describe isoform-specific characteristics among AUF1 ribonucleoprotein complexes, which likely constitute a mechanistic basis for differential functions and regulation among members of this protein family.     

Assembly of Functional Ribonucleoprotein Complexes by AU-rich Element RNA-binding Protein 1 (AUF1) Requires Base-dependent and -independent RNA Contacts

AU-rich element RNA-binding protein 1 (AUF1) regulates the stability and/or translational efficiency of diverse mRNA targets, including many encoding products controlling the cell cycle, apoptosis, and inflammation by associating with AU-rich elements residing in their 3′-untranslated regions. Previous biochemical studies showed that optimal AUF1 binding requires 33–34 nucleotides with a strong preference for U-rich RNA despite observations that few AUF1-associated cellular mRNAs contain such extended U-rich domains. Using the smallest AUF1 isoform (p37^AUF1) as a model, we employed fluorescence anisotropy-based approaches to define thermodynamic parameters describing AUF1 ribonucleoprotein (RNP) complex formation across a panel of RNA substrates. These data demonstrated that 15 nucleotides of AU-rich sequence were sufficient to nucleate high affinity p37^AUF1 RNP complexes within a larger RNA context. In particular, p37^AUF1 binding to short AU-rich RNA targets was significantly stabilized by interactions with a 3′-purine residue and largely base-independent but non-ionic contacts 5′ of the AU-rich site. RNP stabilization by the upstream RNA domain was associated with an enhanced negative change in heat capacity consistent with conformational changes in protein and/or RNA components, and fluorescence resonance energy transfer-based assays demonstrated that these contacts were required for p37^AUF1 to remodel local RNA structure. Finally, reporter mRNAs containing minimal high affinity p37^AUF1 target sequences associated with AUF1 and were destabilized in a p37^AUF1-dependent manner in cells. These findings provide a mechanistic explanation for the diverse population of AUF1 target mRNAs but also suggest how AUF1 binding could regulate protein and/or microRNA binding events at adjacent sites.     

Phosphorylation of p40AUF1 regulates binding to A + U-rich mRNA-destabilizing elements and protein-induced changes in ribonucleoprotein structure

Messenger RNA turnover directed by A + U-rich elements (AREs) involves selected ARE-binding proteins. Whereas several signaling systems may modulate ARE-directed mRNA decay and/or post-translationally modify specific trans-acting factors, it is unclear how these mechanisms are linked. In THP-1 monocytic leukemia cells, phorbol ester-induced stabilization of some mRNAs containing AREs was accompanied by dephosphorylation of Ser83 and Ser87 of polysome-associated p40AUF1. Here, we report that phosphorylation of p40AUF1 influences its ARE-binding affinity as well as the RNA conformational dynamics and global structure of the p40AUF1-ARE ribonucleoprotein complex. Most notably, association of unphosphorylated p40AUF1 induces a condensed RNA conformation upon ARE substrates. By contrast, phosphorylation of p40AUF1 at Ser83 and Ser87 inhibits this RNA structural transition. These data indicate that selective AUF1 phosphorylation may regulate ARE-directed mRNA turnover by remodeling local RNA structures, thus potentially altering the presentation of RNA and/or protein determinants involved in subsequent trans-factor recruitment.     

Identification and characterization of proteins that selectively interact with isoforms of the mRNA binding protein AUF1 (hnRNP D)

The mRNAs that encode certain cytokines and proto-oncogenes frequently contain a typical AU-rich motif that is located in their 3'-untranslated region. The protein AUF1 is the first factor identified that binds to AU-rich regions and mediates the fast degradation of the target mRNAs. AUF1 exists as four different isoforms (p37, p40, p42 and p45) that are generated by alternative splicing. The fact that AUF1 does not degrade mRNA itself had led to the suggestion that other AUF1 interacting proteins might be involved in the process of selective mRNA degradation. Here we used the yeast two-hybrid system in order to identify proteins that bind to AUF1. We detected AUF1 itself, as well as the ubiquitin-conjugating enzyme E2I and three RNA binding proteins: NSEP-1, NSAP-1 and IMP-2, as AUF1 interacting proteins. We confirmed all interactions in vitro and mapped the protein domains that are involved in the interaction with AUF1. Gel-shift assays with the recombinant purified proteins suggest that the interacting proteins and AUF1 can bind simultaneously to an AU-rich RNA oligonucleotide. Most interestingly, the AUF1 interacting protein NSEP-1 showed an endoribonuclease activity in vitro. These data suggest the possibility that the identified AUF1 interacting proteins might be involved in the regulation of mRNA stability mediated by AUF1.