Expression of pituitary tumor transforming gene (PTTG) in human pituitary macroadenomas

The purpose of this study was to elucidate the relationship between pituitary tumor transforming gene (PTTG) and invasiveness in pituitary macroadenomas and to determine the association between PTTG and both the tumor proliferative activity marker proliferation cell nuclear antigen (PCNA) and the angiogenic factor basic fibroblast growth factor. A total of 70 patients with pituitary adenomas who underwent transsphenoidal or craniotomy surgical resection were enrolled. The average age were 42.5?±?13.7 years (17–64 years) for the invasive group and 46.8?±?12.1 years (16–71 years) for the non-invasive group, with no significant difference (P?=?0.179) between the two groups. RT-PCR analysis of a group of pituitary macroadenomas demonstrated that the expression levels of PTTG and PCNA in invasive pituitary adenomas were significantly higher than in non-invasive pituitary adenomas. Both factors are both closely related to the invasive growth of pituitary adenomas and may possibly serve as important markers of this growth. In conclusion, PTTG may promote invasive tumor growth by stimulating pituitary adenomas proliferation. The mechanisms of tumor growth promotion and invasion of the surrounding structures by PTTG need to be further explored.     

垂体瘤转化基因研究进展

垂体瘤转化基因(PTTG)是一个近年来从垂体瘤组织中分离出的原癌基因,进一步研究发现其在多种肿瘤组织及高度增生性组织细胞内高表达.在促进细胞增殖、转化和肿瘤形成中有重要作用,现就其目前研究进展作一综述.     

垂体肿瘤转化基因PTTG在NHL中的表达及其意义

目的：探讨垂体肿瘤转化基因PTTG（pituitary tumor transforming gene）在非霍奇金淋巴瘤（NHL）中的表达，并研究其表达与NHL临床病理指标的关系。方法：采用原位杂交法和免疫组化法检测50例NHL患者肿瘤组织和20例良性淋巴结炎组织中PTTG mRNA及其蛋白的表达。结果：PTTG mRNA在NHL和对照组的阳性表达率分别为54．0％（27／50）和20．0％（4／20），PTTG蛋白在NHL和对照组的阳性表达率分别为50．0％（25／50）和15．0％（3／20），NHL中PTTG mRNA及其蛋白的阳性表达率及表达分级比较均高于对照组。PTTG mRNA的表达与NHL的恶性程度和临床分期呈正相关（r=0．366，P=0．009；r=0．438，P=0．001）。NHL中PTTG mRNA表达与其蛋白表达成等级正相关（r=0．831，P〈0．01）。NHL中PTTG mRNA表达与近期疗效呈负相关（r=-0．354，P〈0．05）。结论：NHL中PTTG高表达。PTTG表达水平与NHL生物学行为可能有关。     

垂体肿瘤转化基因PTTG在NHL中的表达及其意义

目的:探讨垂体肿瘤转化基因PTTG(pituitary tumor transforming gene)在非霍奇金淋巴瘤(NHL)中的表达,并研究其表达与NHL临床病理指标的关系。方法:采用原位杂交法和免疫组化法检测50例NHL患者肿瘤组织和20例良性淋巴结炎组织中PTTG mRNA及其蛋白的表达。结果:PTTG mRNA在NHL和对照组的阳性表达率分别为54.0%(27/50)和20.0%(4/20),PTTG蛋白在NHL和对照组的阳性表达率分别为50.0%(25/50)和15.0%(3/20),NHL中PTTG mRNA及其蛋白的阳性表达率及表达分级比较均高于对照组。PTTG mRNA的表达与NHL的恶性程度和临床分期呈正相关(r=0.366,P=0.009;r=0.438,P=0.001)。NHL中PTTG mRNA表达与其蛋白表达成等级正相关(r=0.831,P<0.01)。NHL中PT-TG mRNA表达与近期疗效呈负相关(r=-0.354,P<0.05)。结论:NHL中PTTG高表达。PTTG表达水平与NHL生物学行为可能有关。     

Strain difference in regulation of pituitary tumor transforming gene (PTTG) in estrogen-induced pituitary tumorigenesis in rats.

Recently a novel oncogene, PTTG (pituitary tumor transforming gene) was isolated from a rat pituitary tumor cell line whose expression is apparently correlated with pituitary tumorigenesis. In the rat, estradiol (E(2)) is known to induce anterior pituitary hyperplasia. The effects of E(2), however, vary greatly among rat strains. Therefore we examined the expression of PTTG and its regulation by E(2) in F344, Wistar, Brown-Norway and Donryu rats. Four-week-old females were ovariectomized and a pellet containing 10 mg of E(2) was given s.c. Total RNA was isolated from the pituitary gland and PTTG mRNA was measured with a competitive RT-PCR technique. The F344 strain was the most susceptible to E(2) induction of pituitary tumorigenesis, followed by Wistar and Brown-Norway, while no increase in pituitary weight was noted in Donryu rats. PTTG mRNA in the gland was induced by E(2) within 48 - 72 h in F344 and Wistar, but not in Brown-Norway or Donryu strains. These data suggest that PTTG expression may at least in part be responsible for strain differences in E(2)-induced pituitary tumorigenesis.     

PTTG 在垂体腺瘤各亚型中的表达与分析

目的:研究PTTG与垂体瘤的各亚型的相关性.方法:用免疫组化方法检测92例垂体肿瘤病人PTTG.其中29例GH,20例PRL,10例ACTH,11例FSH/LH,9例TSH和13例无功能腺瘤.结果:PTTG在细胞质内显著表达,各亚型中GH型是表达最高,PRL腺瘤表达最低,各亚型的阳性表达率与PRL亚型阳性表达率对比均有统计学意义.结论:重体腺瘤不同垂体亚型中PTTG的表达阳性率及表达强度不同,PTTG检测,可为早期诊断垂体腺瘤( GH、PRL、ACTH、FSH/LH、TSH)亚型和无功能型提供参考.     

非霍奇金淋巴瘤患者骨髓垂体瘤转化基因、c-myc基因表达的研究

目的 探讨非霍奇金淋巴瘤（NHL）患者骨髓垂体瘤转化基因（PTTG）与c-myc基因的表达及其临床意义.方法 采用反转录聚合酶链反应（RT-PCR）法检测38例NHL患者骨髓及10例慢性淋巴结炎患者骨髓单个核细胞（BMMNC）中PTTG及c-myc基因的表达.结果 NHL患者骨髓中PTTG和c-myc基因的表达水平均明显高于慢性淋巴结炎组,差异有统计学意义（PTTG：0.567 7±0.270 7比0.071 2±0.020 1,t=4.706,P＜0.05; c-myc：0.352 6±0.185 4比0.107 3±0.043 5,t=3.303,P=0.002）.外周T细胞淋巴瘤和弥漫大B细胞淋巴瘤患者PTTG及c-myc基因表达水平差异均无统计学意义（PTTG：0.556 8±0.211 3比0.602 8±0.244 6,t=0.640,P=0.527;c-myc：0.350 1±0.177 6比0.361 0±0.190 2,t=0.302,P=0.765）.PTTG基因的表达与NHL骨髓浸润、国际预后指数（IPI）评分呈正相关（r=0.422,r=0.387;均P＜0.05）.c-myc基因的表达与NHL骨髓浸润、IPI评分呈正相关（r=0.431,r=0.344,均P＜0.05）.NHL患者骨髓PTTG基因和c-myc基因的表达呈正相关（r=0.490,P＜0.05）.结论 NHL中PTTG、c-myc呈高表达状态,PTTG可能通过直接或间接途径促进c-myc的高表达.     

食管鳞癌组织垂体瘤转化基因表达及其临床意义的研究

目的:探讨食管鳞癌组织中垂体瘤转化基因(PTTG)mRNA及其蛋白的表达?与肿瘤临床病理特征的关系.方法:采用RT-PCR技术检测30例食管鳞癌及相应的30例癌旁组织中PTTG mRNA的表达,同时采用免疫组织化学SP法检测标本中PTTG蛋白的表达.结果:在食管鳞癌组织中PTTGmRNA的阳性表达率(93.3%)及平均表达水平(0.69±0.06)显著高于相应的癌旁正常组织(70.0%和0.32±0.06),两组比较差异有统计学意义,P<0.01.PTTG蛋白在食管鳞癌组织中的阳性表达(83.3%,25/30)明显高于在癌旁组织中的阳性表达(20.0%,6/30),P<0.01;并与淋巴结转移、TNM分期和分化程度有关.结论:PTTG基因异常表达可对食管鳞癌的发生和发展起重要作用,可能为食管鳞癌的早期诊断和基因治疗提供新的靶点.     

Pituitary tumour transforming gene (PTTG) induces genetic instability in thyroid cells

Cancer reflects the progressive accumulation of genetic alterations and subsequent genetic instability of cells. Cytogenetic studies have demonstrated the importance of aneuploidy in differentiated thyroid cancer development. The pituitary tumour transforming gene (PTTG), also known as securin, is a mitotic checkpoint protein which inhibits sister chromatid separation during mitosis. PTTG is highly expressed in many cancers and overexpression of PTTG induces aneuploidy in vitro. Using fluorescent intersimple sequence repeat PCR (FISSR-PCR), we investigated the relationship between PTTG expression and the degree of genetic instability in normal and tumorous thyroid samples. The genomic instability index (GI index) was 6.7-72.7% higher in cancers than normal thyroid tissues. Follicular thyroid tumours exhibited greater genetic instability than papillary tumours (27.6% (n=9) versus 14.5% (n=10), P=0.03). We also demonstrated a strong relationship between PTTG expression and the degree of genetic instability in thyroid cancers (R2=0.80, P=0.007). To further investigate PTTG's role in genetic instability, we transfected FTC133 thyroid follicular cells and observed increased genetic instability in cells overexpressing PTTG compared with vector-only-transfected controls (n=3, GI Index VO=29.7+/-5.2 versus PTTG=63.7+/-6.4, P=0.013). Further, we observed a dose response in genetic instability and PTTG expression (GI Index low dose (0.5 microg DNA/ six-well plate) PTTG=15.3%+/-1.7 versus high dose (3 microg DNA) PTTG=50.8%+/-3.3, P=0.006). Overall, we describe the first use of FISSR-PCR in human cancers, and demonstrate that PTTG expression correlates with genetic instability in vivo, and induces genetic instability in vitro. We conclude that PTTG may be an important gene in the mutator phenotype development in thyroid cancer.     

大肠腺癌组织PTTG和VEGF-A及p53表达生物学意义的探讨

目的:探讨垂体瘤转化基因(PTTG)、血管生成内皮因子(VEGF)、p53蛋白和微血管密度(MVD)与大肠腺癌的发生发展及临床病理因素之间的关系。方法:免疫组化检测18例正常大肠黏膜组织、20例大肠腺瘤组织和44例大肠腺癌组织中PTTG、VEGF和p53表达及MVD值,分析各指标之间的相关性。结果:PTTG在正常大肠、大肠腺瘤和大肠腺癌组织中的阳性率为11.1%(2/18)、75.0%(15/20)和88.6%(39/44),VEGF阳性率为11.1%(2/18)、40.0%(8/20)和70.4%(31/44)。p53在正常大肠组织中无表达,在大肠腺瘤及大肠腺癌中的阳性表达率为50.0%(10/20)、68.2%(30/44);MVD在大肠腺癌、大肠腺瘤及正常大肠组织中的平均密度值为67±26、33±7和11±4。在大肠腺癌中PTTG和VEGF呈正相关(r=0.46,P<0.05),PTTG与p53蛋白的表达呈正相关(r=0.51,P<0.05),VEGF和p53蛋白呈正相关,r=0.32,P<0.05。结论:PTTG、VEGF和p53参与大肠腺癌的发生、发展,三者相互作用促进大肠癌新生血管的生成,促进肿瘤浸润和转移及脉管瘤栓的形成,三者可以作为大肠癌早期诊断和判断预后的有效参考指标。     

Overexpression of human pituitary tumor transforming gene (hPTTG), is regulated by beta-catenin /TCF pathway in human esophageal squamous cell carcinoma

Overexpression of human pituitary tumor transforming gene (PTTG) is wildly detected in many tumors, including esophageal cancer. Besides overexpression of PTTG in esophageal squamous cell carcinoma (ESCC) tissues and cells, we detected accumulation of cytoplasmic beta-catenin in ESCC. In our study, a putative TCF4-binding element (TBE) was identified in PTTG promoter region. The activity of PTTG promoter containing the TBE was activated by S37Abeta-catenin and inhibited by dominant-negative TCF. Furthermore, the activation by S37Abeta-catenin was mostly abrogated among PTTG promoter region without the TBE or with a mutant one. By using biotin-streptavidin pull-down assay, we also found that the TBE among PTTG promoter bound to TCF-4 protein. Moreover, levels of PTTG mRNA and protein were increased by S37Abeta-catenin. Finally, it is noticeable that we detected a correlation between beta-catenin localization and PTTG expression in 69 primary ESCC (p<0.01). In brief, our study shows that overexpression of PTTG in ESCC is likely due to the activation of beta-catenin/WNT signaling. As a target gene of beta-catenin/TCF pathway, PTTG may play an important role in tumorigenesis of human ESCC.     

Thyroid hormone receptors suppress pituitary tumor transforming gene 1 activity in hepatoma

Pituitary tumor transforming gene 1 (PTTG1) is expressed in most tumors. However, whether thyroid hormone (T(3)) and its receptors (TR) regulate PTTG1 in human hepatocellular carcinomas (HCC) remains unclear. Previous cDNA microarrays revealed PTTG1 is down-regulated by T(3)/TR. This study investigated the significance of PTTG1 regulation by T(3) in HCC cells. The PTTG1 mRNA and protein expression were repressed by T(3) in HCC cell lines overexpressing TR. However, after knockdown of TRs expression by RNA interference, PTTG1 repression by T(3) was abolished. Similar results were observed in thyroidectomized rats. To localize the regulatory region in the PTTG1 promoter, serial deletions within the PTTG1 promoter region were constructed. The promoter activity of the PTTG1 gene was repressed (25-51%) by T(3). Additionally, these findings indicate that PTTG1 may be regulated by Sp1. The critical role of the -594 and -520 Sp1 binding sites was confirmed by electrophoretic mobility shift assay. Transfection with Sp1 expression vector enhanced the activity of the PTTG1 promoter fragment reporter. Also, Sp1 was down-regulated in HCC cells and in thyroidectomized rat after T(3) treatment. Additionally, ectopic expression of PTTG1 promotes cell proliferation in Hep3B hepatoma cells. Conversely, knockdown of PTTG1 or Sp1 expression reduced cell proliferation in HepG2 cells. Notably, the expression of PTTG1 and Sp1 was inversely correlated with the expression of TR proteins in HCC. Together, these findings indicate that PTTG1 gene expression is mediated by Sp1 and is indirectly down-regulated by T(3). Finally, overexpression of PTTG1 or SP1 in HCCs is TR-dependent and crucial in the development of HCC.     

Regulation of angiogenesis and invasion by human Pituitary tumor transforming gene (PTTG) through increased expression and secretion of matrix metalloproteinase-2 (MMP-2)

Background  

Pituitary tumor transforming gene (PTTG) is a novel oncogene that is expressed at higher level in most of the tumors analyzed to date compared to normal tissues. Existence of a relationship between PTTG levels and tumor angiogenesis and metastasis has been reported. However, the mechanisms by which PTTG achieve these functions remain unknown. In the present study, we investigated the effect of overexpression of PTTG on secretion and expression of metastasis-related metalloproteinase-2 (MMP-2) in HEK293 cells, cell migration, invasion and tubule formation.     

Expression of esophageal cancer related gene 4 (ECRG4), a novel tumor suppressor gene,in esophageal cancer and its inhibitory effect on the tumor growth in vitro and in vivo

The ECRG4 gene was initially identified and cloned in our laboratory from human normal esophageal epithelium (GenBank accession no. AF325503). We revealed the expression of ECRG4 protein was downregulated in 68.5% (89/130) ESCC samples using tissue microarray. The low ECRG4 protein expression was significantly associated with regional lymph node metastasis, primary tumor size, and tumor stage in ESCC (p < 0.05). ECRG4 mRNA expression was downregulated in ESCC due to the hypermethylation in the gene promoter. The treatment with 5‐aza‐2′‐deoxycytidine, which is a DNA methyltransferase inhibitor restored ECRG4 mRNA expression in ESCC cells. The result indicated that promoter hypermethylation may be 1 main mechanism leading to the silencing of ECRG4. The high expression of ECRG4 in patients with ESCC was associated with longer survival compared with those with low ECRG4 expression by Kaplan‐Meier survival analysis (p < 0.05). ECRG4 protein was an independent prognostic factor for ESCC by multivariable Cox proportional hazards regression analysis (p < 0.05). The restoration of ECRG4 expression in ESCC cells inhibited cell proliferation, colony formation, anchorage‐independent growth, cell cycle progression and tumor growth in vivo (p < 0.05). The transfection of ECRG4 gene in ESCC cells inhibited the expression of NF‐κB and nuclear translocation, in addition to the expression of COX‐2, a NF‐κB target gene, was attenuated. Taken together, ECRG4 is a novel candidate tumor suppressor gene in ESCC, and ECRG4 protein is a candidate prognostic marker for ESCC. © 2009 UICC     

Role of the pituitary tumor transforming gene 1 in the progression of hepatocellular carcinoma

In order to demonstrate the role of the pituitary tumor transforming gene 1 (PTTG1) in the development of hepatocellular carcinoma (HCC) and its value as a molecular target for cancer therapy, we analyzed the expression of PTTG1 mRNA and protein, and their relation to clinicopathological characteristics and basic fibroblast growth factor (bFGF) expression in HCC. It was observed that the level of PTTG1 mRNA and the positive rate of PTTG1 protein in cancerous tissues were significantly higher than that in adjacent non-cancerous tissues (both P< 0.001). The PTTG1 protein levels were correlated with several clinicopathological parameters, including alpha-fetoprotein level, portal vein tumor thrombosis, tumor stage, and bFGF protein level (P< 0.05). The proliferation indices were significantly less and the apoptotic rates were significantly higher in the HepG2 and SMMC-7721 cells treated with PTTG1 siRNA transfection than their untransfected counterparts. The expressions of Caspase-3, Bax, p21 and p53 in HepG2 and SMMC-7721 cells were significantly increased after siRNA knockdown of PTTG1 expression. In conclusion, the PTTG1 gene is up-regulated in the cancerous tissue from patients with HCC and involved in the progression of HCC. Inhibiting PTTG1 expression decreases cell proliferation and induces apoptosis in hepatic cancer cell lines, indicating that PTTG1 may be a new therapeutic target for HCC treatment.     

Increased expression of pituitary tumor-transforming gene (PTTG)-1 is correlated with poor prognosis in glioma patients

Pituitary tumor-transforming gene (PTTG), which is homologous to a mammalian securin, plays a pivotal role in cell transformation and is overexpressed in numerous cancer cell lines and tissues. PTTG functions in the control of mitosis, cell transformation, DNA repair and gene regulation. In the present study, we investigated whether the expression of PTTG1 is correlated with tumorigenicity and prognosis in glioma patients. Expression of PTTG1 was confirmed in three glioma cell lines at the mRNA and protein levels using RT-PCR analysis and Western blotting, respectively. Furthermore, PTTG1 protein was detected in 44 glioma tissue samples using immunohistochemical techniques, markedly increased in high-grade gliomas compared to low-grade gliomas and associated with an unfavorable patient outcome. Moreover, siRNA against the PTTG1 gene inhibited cell proliferation and invasion in glioma cell lines. These data suggest that increased expression of PTTG1 contributes to the tumorigenicity of glioma cells and may be useful as a prognostic marker for glioma patients.     

人垂体肿瘤转化基因1在卵巢癌组织中的表达及其意义

背景与目的:人垂体肿瘤转化基因1(humanpituitarytumortransforminggene1,hPTTG1)是新近发现的一个癌基因。我们用基因表达谱芯片对晚期卵巢低分化浆液性癌进行卵巢癌相关基因的筛查,发现该基因在这种卵巢癌中明显高表达。本研究对不同临床分期、不同病理类型及不同组织学分级的上皮性卵巢癌组织hPTTG1的表达进行检测,探讨该基因在卵巢癌发生发展中的作用。方法:用非竞争性RT-PCR方法半定量检测27例卵巢癌及4例正常卵巢组织中hPTTG1mRNA的表达,用免疫组化方法检测该27例卵巢癌及18例正常卵巢组织中hPTTG1蛋白的表达。结果:在正常卵巢组织中hPTTG1mRNA有低水平的表达,而卵巢癌组织hPTTG1mRNA表达高于正常,两者之间有显著性差异(P<0.01),卵巢癌组织较正常卵巢组织表达倍增1.1～4.8,中位倍增2.4。进一步分析卵巢癌组织中hPTTG1mRNA表达水平与临床分期及病理分级的关系,未发现hPTTG1mRNA表达水平的高低与临床分期具有相关性,但发现hPTTG1mRNA倍增与肿瘤分化程度密切相关(r=0.686,P<0.05)。hPTTG1蛋白在所有卵巢癌组织中表达,而在正常卵巢组织中未检测到hPTTG1蛋白的表达。结论:hPTTG1表达在早期卵巢癌即发生改变,其表达可能与不良分化有关;hPTTG1在卵巢癌组织中高表达,可能是卵巢癌的一个分子标志。     

食管癌p63 基因mRNA的异常表达

目的 研究p63基因mRNA在原发性食管鳞癌的表达情况,了解该基因在原发性食管鳞癌发生、发展和预后中的意义。方法 采用RT-PCR检测了38例原发性食管鳞状上皮癌及对应的正常组织p63 基因mRNA的表达情况。结果 73.68 %（28/ 38） 原发性食管鳞状上皮癌检测到ΔNp63 基因mRNA 的表达，而对照组38 例正常组织中有30 例（78.94%）表达ΔNp63 基因mRNA,其中低分化癌的表达率高于高、中分化癌（ P〈0.05），而与年龄、性别、淋巴结转移和临床分期无关.全部样本中仅1例检测有TAp63mRNA的表达。结论 p63在食管癌和上皮细胞中表达的亚型主要是ΔNp63，其在低分化组的高表达,说明ΔNp63参与了食管鳞癌的发生、发展，并与食管鳞癌的预后有关。     

PTTG、bFGF和endostatin在大肠癌中的表达

目的:探讨大肠癌组织中垂体肿瘤转化基因(PTTG),碱性成纤维细胞生长因子(bFGF)和内皮抑素(endostatin)在大肠癌表达的意义。方法:应用免疫组化法测定57例大肠癌标本中的PTTG,bFGF和en-dostatin的表达水平。并对其与临床病理特征的关系进行分析。结果:PTTG,bFGF和endostatin在大肠癌组织中的表达均与Dukes分期,分化程度,有无淋巴结转移相关,与患者性别、病理类型无关。PTTG表达同bF-GF表达存在显著正相关,而endostatin表达与PTTG和bFGF呈负相关。结论:大肠癌的侵袭性可能与PTTG和bFGF表达增高及endostatin表达下调有关。