肝细胞癌患者中p53基因变化的相关因素分析

ｐ５３基因的变化已被认为是肿瘤病因学和分子发病机制的重要线索。为了阐明ＨＣＣ的主要致病因子及其在ＨＣＣ发病机制中的相对意义，本研究对ｐ５３基因变化较常见的中国南部地区的７０例ＨＣＣ患者采用Ｘ＾２检验等，分析一般资料、嗜肝病毒感染和病理资料与ｐ５３基因的ＬＯＨ则与嗜肝病毒感染和癌周组织中的肝硬化程度相关。以上结果提示，ＨＣＣ的主要致病因素是嗜肝病毒感染和高度流行区的某些其它因素，其中嗜肝病毒感染在Ｈ     

Microsatellite instability in human hepatocellular carcinoma: relationship to p53 abnormalities

ABSTRACT— Aims/Background: Microsatellite instability was sought in 10 human hepatocellular carcinomas (HCCs) to determine whether defective DNA mismatch repair might be implicated in the multiple genetic alterations observed in the p53 tumor suppressor gene in some of these patients' tumors. Methods: Genomic DNA from HCCs and adjacent non-tumorous livers was subjected to PCR with primers for nine microsatellites, and PCR products were resolved in a denaturing gel. Microsatellite instability was defined as the presence of band shifts or additional bands for at least two microsatellite sequences in an HCC compared to the nontumorous liver tissue from the same patient. Results: Microsatellite instability was detected in four of ten HCCs. Three of these four HCCs did not have p53 exon mutations. However, one HCC had microsatellite instability as well as multiple p53 exon mutations and multiple intron alterations. Four other patients with multiple p53 intron alterations in HCC (compared to their own nontumorous liver), three of whom also had a mutation in the exons, had no microsatellite instability. Conclusions: Defective DNA mismatch repair, as indicated by microsatellite instability, might have played a role in hepatocarcinogenesis in four of the ten patients, but in general it was not associated with p53 alterations. In one of the ten patients, defective DNA mismatch repair might have been the cause of multiple mutations in both the coding and intron sequences of the p53 gene.     

Role of p53 suppression in the pathogenesis of hepatocellular carcinoma

In the world, hepatocellular carcinoma (HCC) is among the top 10 most prevalent malignancies. HCC formation has indeed been linked to numerous etiological factors, including alcohol usage, hepatitis viruses and liver cirrhosis. Among the most prevalent defects in a wide range of tumours, notably HCC, is the silencing of the p53 tumour suppressor gene. The control of the cell cycle and the preservation of gene function are both critically important functions of p53. In order to pinpoint the core mechanisms of HCC and find more efficient treatments, molecular research employing HCC tissues has been the main focus. Stimulated p53 triggers necessary reactions that achieve cell cycle arrest, genetic stability, DNA repair and the elimination of DNA-damaged cells’ responses to biological stressors (like oncogenes or DNA damage). To the contrary hand, the oncogene protein of the murine double minute 2 (MDM2) is a significant biological inhibitor of p53. MDM2 causes p53 protein degradation, which in turn adversely controls p53 function. Despite carrying wt-p53, the majority of HCCs show abnormalities in the p53-expressed apoptotic pathway. High p53 in-vivo expression might have two clinical impacts on HCC: (1) Increased levels of exogenous p53 protein cause tumour cells to undergo apoptosis by preventing cell growth through a number of biological pathways; and (2) Exogenous p53 makes HCC susceptible to various anticancer drugs. This review describes the functions and primary mechanisms of p53 in pathological mechanism, chemoresistance and therapeutic mechanisms of HCC.     

肝细胞癌中p53基因突变的检测及新DNA片段的发现

目的：检测原代肝癌组织以及肝癌细胞系中ｐ５３的突变位点和频率,了解ｐ５３突变与肝癌发病和治疗的关系。方法：设计了３对引物,采用ＰＣＲ技术扩增ｐ５３的５－８外显子,然后进行ＤＮＡ测序鉴定,共测定了两个肝癌细胞系（ＢＥＬ－７４０２和２．２．１５）以及两例原代肝癌组织,其中５和６外显子用一对引物串联扩增出来,上游引物序列为５′－ＧＧＡＡＴＴＣＣＴＣＴＴＣＣＴＧＣＡＧ－３′,下游为：５′－ＧＧＡＡＴＴＣＡ     

Human tumor p53 mutations are selected for in mouse embryonic fibroblasts harboring a humanized p53 gene

To date, there has been no way to examine induced human p53 gene mutations in cell cultures exposed to mutagenic factors, other than by restriction site analysis. Here, we used embryonic cells from our Hupki (human p53 knock-in) mouse strain to generate human p53 DNA-binding domain (DBD) mutations experimentally. Twenty cultures of untreated primary mouse Hupki fibroblasts and 20 short-wavelength UV light (UVC)-treated cultures (20J/m(2)) were passaged >20 times. Established Hupki embryonic fibroblast cell lines (HUFs) were genotyped by dideoxy DNA sequencing of p53 exons 4-9. Seven of the HUFs harbored point mutations in the humanized p53 DBD. Of the 9 mutations (6 single- and 1 triple-site mutation), 2 were at the most frequently mutated codons in human cancers (c.248 and c.273). The Affymetrix p53 GeneChip assay also readily identified the 6 single-base substitutions. All mutations in HUFs from UV-treated cultures were at dipyrimidine sites, including 3 nontranscribed strand C -->T transitions. The mutant HUFs were deficient in p53 transactivation function, and missense mutants had high levels of nuclear p53 protein. In a second experiment, primary Hupki cells were exposed to the carcinogen aristolochic acid I (AAI). Five of 10 cultures that became established within 2 months harbored p53 DBD mutations. All were transversions, including 4 A --> T substitutions on the nontranscribed strand, a hallmark of DNA mutation by AAI. We conclude that establishment of Hupki mouse fibroblasts in culture readily selects for p53 DBD mutations found in human tumors, providing a basis for generating experimental mutation patterns in human p53.     

p73、PTEN 在胃癌中的表达

目的 检测肿瘤相关基因p73、肿瘤抑制基因PTEN（phosphatase and tensin homolog deleted on chromosometen）在胃癌组织中的表达，并研究其临床病理意义。方法 采用逆转录聚合酶链式反应（RT-PCR）法检测p73、PTEN在40例胃癌中的表达。结果 ①PTNM（pathological tumor-node-metastasis）分期Ⅰ、Ⅱ期胃癌与对照组正常胃黏膜组织间p73、PTEN的表达均有非常显著性差异（P〈0．01）；PTNM分期Ⅲ、Ⅳ期和Ⅰ、Ⅱ期胃癌p73、PTEN的表达均有非常显著性差异（P〈0．05）；②p73在高、中分化胃腺癌组与低分化腺癌组阳性率表达无显著性差异（P〉0．05）；而PTEN在高、中分化腺癌和低分化腺癌阳性率表达差异具有显著性（P〈0．05）。③p73、PTEN在有淋巴结转移组和无淋巴结转移组检出阳性率差异具有显著性（P〈0．05）。结论 p73、PTEN的表达与胃癌临床病理特征和生物学行为存在密切关系，p73、PTEN基因是胃癌细胞增生活跃的重要影响因素。     

The mutation of codon 249 in the p53 gene is not specific in Japanese hepatocellular carcinoma

ABSTRACT— Hepatocellular carcinoma samples obtained from 59 patients at surgical resection were examined for mutations of the third base at codon 249 of the p53 gene, using the polymerase chain reaction and oligonucleotide hybridization techniques. This point mutation, which is frequently observed in HCC cases from Southern Africa and Quidong in China, was not recognized in either 60 hepatocellular carcinomas or 53 noncancerous liver tissue samples from Japan. Thirty-four of 45 patients (75.6%) were positive for the hepatitis C virus, which was a higher rate than that for hepatitis B virus infection (9 of 55; 16.4%). The exposure to aflatoxin B1 was not considered to be remarkable. These results suggest that the point mutation of the third base at codon 249 is not common in Japanese patients, and it is suggested that numerous other factors affect the mutation of the p53 gene and the development of hepatocellular carcinoma.     

Detection of BCL-6 rearrangements and p53 mutations in malt-lymphomas

Twenty-seven lymphomas of mucosa-associated lymphoid tissue (MALT) derived from distinct anatomical sites were tested for the presence of genetic lesions commonly involved in B-cell lymphomagenesis, including activation of proto-oncogenes (BCL-1, BCL-2, BCL-6, and c-MYC), disruption of tumor suppressor loci (p53, 6q), and infection by viruses [Epstein-Barr virus (EBV), and Kaposi's sarcoma-herpesvirus/human herpesvirus-8 (KSHV/HHV-8)]. Sixteen low-grade and 11 high-grade MALT-lymphomas were included in the study. The presence of genetic lesions was tested by a combination of molecular approaches, including Southern blot hybridization, polymerase chain reaction (PCR), and PCR-single strand conformation polymorphism followed by DNA direct sequencing. Alterations of BCL-1, BCL-2, or c-MYC, as well as infection by KSHV/HHV-8, scored negative in all MALT-lymphomas analysed. Conversely, rearrangements of BCL-6 and mutations of p53 clustered with a fraction of high-grade MALT-lymphomas. Deletions of 6q occurred in selected cases of both low- and high-grade MALT-lymphomas, whereas a monoclonal infection by EBV was restricted to one single patient. These data corroborate the notion that the molecular pathogenesis of MALT-lymphomas differs substantially from that of nodal B-cell lymphomas. Occasionally, however, a proportion of high-grade MALT-lymphomas may harbor selected genetic lesions among the ones commonly involved in nodal B-cell lymphomagenesis. Am. J. Hematol. 56:206–213, 1997. © 1997 Wiley-Liss, Inc.     

良恶性肝病C-erbB-2和p53基因表达比较

目的　了解癌基因ＣｅｒｂＢ２ 和Ｐ５３ 在良恶性肝病中的表达情况,分析其在肝细胞癌癌变过程中发生的作用．方法　用ｃＤＮＡｍ ＲＮＡ 原位杂交技术和免疫组化对２２ 例肝硬变,１１ 例癌前病变、即肝小细胞非典型增生,３５ 例肝癌及５ 例正常肝组织进行检测．结果　ＣｅｒｂＢ２ ｍ ＲＮＡ 的杂交阳性率在正常肝、肝小细胞非典型增生、肝硬变、分化较好肝癌组和分化较差肝癌组分别为０ ,７３ ％ ,６４ ％ ,３７ ％ 和２５ ％ ;ＣｅｒｂＢ２ 蛋白阳性率分别为０ ,１００ ％ ,８２ ％ ,４５ ％ 和２９ ％ ． Ｐ５３ ｍ ＲＮＡ 的杂交阳性率在正常肝、肝小细胞非典型增生（ＳＬＣＤ） 、肝硬变、分化较好肝癌组和分化较差肝癌组分别为０ ,７３ ％ ,６８ ％ ,３６ ％ 和２５ ％ ;Ｐ５３ 蛋白阳性率分别为０ ,０ ,０ ,２７ ％ 和４２ ％ ． 蛋白阳性物只见于肝癌细胞．结论　ＣｅｒｂＢ２ 癌基因可能在肝癌癌变的早期阶段起作用,主要作用于ＳＬＣＤ、胆管细胞、增生肝细胞． 野生型Ｐ５３ 有抗癌作用,突变型Ｐ５３ 致癌作用可能发生于肝癌癌变较晚阶段．     

肝细胞癌CD44v6和p16基因蛋白的表达及其意义

目的探讨CD44v6和p16基因蛋白表达与肝细胞癌(HCC)转移和预后的关系。方法应用免疫组织化学方法,检测分析110例HCC组织中CD44v6及p116蛋白表达,结合随访资料分析。结果在HCC中,CD44v6和p16阳性表达率分别为42.7%和34.5%。CD44v6阳性表达的HCC转移率高(P<0.05),分化程度和患者>5年生存率低(P<0.05);p16阳性表达的HCC转移率低(P<0.05),分化程度和患者>5年生存率高(P<0.05)。CD44v6与p16表达呈负相关(r=-0.59,P<0.005)。结论CD44v6和p16表达与HCC转移和患者生存期密切相关,检测CD44v6和p16蛋白的表达可作为判断HCC预后的参考指标。     

p53 gene in treatment of hepatic carcinoma： Status quo

Hepatocellular carcinoma(HCC)is one of the 10 most common cancers worldwide.There is no ideal treatment for HCC yet and many researchers are trying to improve the effects of treatment by changing therapeutic strategies.As the majority of human cancers seem to exhibit either abnormal p53 gene or disrupted p53 gene activation pathways,intervention to restore wild-type p53 (wt-p53)activities is an attractive anti-cancer therapy including HCC.Abnormalities of p53 are also considered a predisposition factor for hepatocarcinogenesis.p53 is frequently mutated in HCC.Most HCCs have defects in the p53-mediated apoptotic pathway although they carry wt-p53.High expression of p53 in vivo may exert therapeutic effects on HCC in two aspects(1)High expression of exogenous p53 protein induces apoptosis of tumor cells by inhibiting proliferation of cells through several biologic pathways and(2)Exogenous p53 renders HCC more sensitive to some chemotherapeutic agents.Several approaches have been designed for the treatment of HCC via the p53 pathway by restoring the tumor suppression function from inactivation,rescuing the mutated p53 gene from instability,or delivering therapeutic exogenous p53.Products with p53 status as the target have been studied extensively in vitro and in vivo.This review elaborates some therapeutic mechanisms and advances in using recombinant human adenovirus p53 and oncolytic virus products for the treatment of HCC.     

寡核苷酸芯片技术检测中国肝细胞癌p53基因点突变

目的探讨寡核苷酸芯片技术在我国肝细胞癌p53基因点突变发生频率及形式,并以DNA测序法进行验证。方法参照国际p53突变公共数据库资料,以发生频率最高的7个点突变序列设计探针,制备p53基因点突变专用寡核苷酸芯片,应用该技术检测我国肝细胞癌p53基因7个常见突变位点的突变频率及形式,以DNA测序法验证结果,比较不同分组时p53基因点突变差异。结果共检测肝细胞癌石蜡包埋标本54例,p53基因突变率为38.9%(21/54)。54例中广西肝癌高发病区组17例,广西低发病区组(低发区组)19例,区(省)外组18例,三组突变率分别为47%、21%、50%。p53突变主要发生在249编码区,主要突变形式为249ser突变(由AGG→AGT,第三碱基G→T颠换);以DNA测序法对结果进行验证,两种技术检测结果重合率100%。结论寡核苷酸芯片技术可作为检测肝癌p53基因突变的一种新的、可靠和便捷的手段;我国肝癌不同地区之间p53基因突变在频率及形式上既有差异性又有类似性,可能预示不同地区肝细胞癌的病因学异同性。     

P27基因在原发性肝癌中的表达及其与预后的关系

目的　探讨 P2 7在原发性肝癌中表达 ,揭示其与原发性肝癌临床病理指标和预后的关系。方法　采用免疫组化二步法 ,检测 4 3例原发性肝癌标本、2 1例肝硬化标本和 16例正常肝脏组织中的 P2 7表达情况 ,并对2 9例肝癌患者进行了随访。结果　 P2 7在正常肝脏组织中少有表达 ,肝硬化组阳性表达有所增加 ,但两组之间差异无显著性 (P>0 .0 5 ) ;P2 7在原发性肝癌组中阳性表达率为 86 .0 4 % ,与肝硬化组和正常对照组相比差异有显著性(P<0 .0 1)。肿瘤直径 >5 cm、多个瘤灶、低分化和有血管侵犯的原发性肝癌组织中 P2 7呈低表达 ;P2 7高表达的原发性肝癌患者较低表达者生存期明显延长 (P<0 .0 1)。结论　 P2 7基因在原发性肝癌组织中的表达有组织特异性 ;P2 7与原发性肝癌的浸润和转移有密切关系 ,可以作为原发性肝癌的预后判断指标之一     

野生型P53基因诱导血管平滑肌细胞P21基因表达

为研究野生型P53基因导入诱导血管平滑肌细胞P21基因的表达，探讨P53基因调节细胞周期进程的作用机理，体外培养了人脐动脉平滑肌细胞。将野生型P53基因导入细胞后，应用逆转录－聚合酶链反应半定量测定P21mRNA水平，以免疫组织化学法观察P21蛋白表达的变化，并用流式细胞术分析细胞周期。结果发现，正常生长的血管平滑肌细胞中P21mRNA水平较低，用免疫组织化学法检测不到P21蛋白。野生型P53基因导入并在平滑肌细胞中表达后，显著增加了P21mRNA水平，在免疫组织化学检测中呈现很强的阳性显色反应、引起平滑肌细胞停滞在G0／G1期。以上结果提示，野生型P53基因通过诱导P21基因表达调控血管平滑肌细胞周期。     

p53 Gene mutations and overexpression of p53 product in cancerous and noncancerous biliary epithelium in patients with pancreaticobiliary maljunction

To investigate the molecular mechanisms of the high incidence of carcinogenesis in the biliary epithelium of patients with pancreaticobiliary maljunction, we examined p53 gene mutations, loss of heterozygosity of p53, and overexpression of p53 gene product in the cancerous and noncancerous biliary epithelium of 27 patients with pancreaticobiliary maljunction. Mutations of the p53 gene were examined by polymerase chain reaction-single strand conformation polymorphism and a direct sequencing method. Loss of heterozygosity of the p53 gene was determined using a double-targeted fluorescence in situ hybridization method. Expression of p53 gene product was examined using immunohistochemical staining. Mutations of the p53 gene were found in 4 of 5 biliary carcinomas (80%) and in 10 of 26 noncancerous biliary lesions (38.5%). Point mutations of the p53 gene were detected at codons 207, 212, and 217 on exons 5 through 8. The incidence of p53 gene mutations on exons 5, 6, 7, and 8 was 12.9%, 36.4%, 0.0%, and 13.8%, respectively. Loss of heterozygosity of p53 was shown in 72% of the cells obtained from the cancerous lesion, and in an average of 14% obtained from the noncancerous lesions. Overexpression of p53 protein was found in 57.1% of carcinoma, and in 31.3% of the noncancerous lesions. These results suggest that p53 gene mutations are involved in the carcinogenesis of biliary epithelium in patients with pancreaticobiliary maljunction.     

p53对肝癌P-糖蛋白的表达和耐药表型的影响

目的 证明野生型p53调节肝癌细胞P－糖蛋白（p-glycoprotein,P-gp)表达的设想。方法 通过采用脂质体介导转染技术,将野生型p53 cDNA导入一种p53和Rb基因缺失的肝癌细胞株Hep3B。结果 经G418筛选获得稳定整合了野生型p53的克隆（wt-p53)和空载体克隆（pNeo);经northern和western印迹鉴定,wt-p53细胞表达p53;p21waf1/cip1蛋白的升高证实wt-p53细胞的p53有转录活性,并致使P－gp表达降低。细胞毒性试验表明：与pNeo细胞相比,wt-p53细胞对阿霉素和丝裂霉素化疗敏感。流式细胞仪显示：wt-p53细胞的阿霉素荧光量为pNeo细胞的13倍。结论 在肝癌细胞Hep3B中重建野生型p53的活性由于降低P－gp的表达而对化疗药敏感。     

Mutations in the p53 Gene in Acute Myeloid Leukemia Patients Correlate with Poor Prognosis

Inactivation of tumor suppressor genes, whose products exert an inhibitory influence on cell cycle progression, can lead to neoplastic transformation. In acute myeloid leukemia (AML), the frequency of p53 gene mutations ranges from 4 to 15% in populations from USA and Europe. In an attempt to investigate the frequency of point mutations in the p53 gene in AML Brazilian patients, DNA samples of 35 patients were studied using PCR-SSCP techniques, screening exons 4–10. Mutations were identified in bone marrow DNA in 5 of the 35 AML patients (14.3%), a frequency similar to those reported for Northern American and European populations. The overall survival of patients with mutations in the p53 gene was significantly shorter than for patients without mutations.     

Expression of maspin in colon cancers: its relationship with p53 expression and microvessel density

We studied the expression of maspin in colonic adenocarcinoma compared with adenoma and metastatic adenocarcinoma as well as the relationship with its possible regulator, p53. The colonic specimens consisted of 24 adenomas, 49 adenocarcinomas, and 17 metastatic adenocarcinomas. Immunohistochemical staining of paraffin sections was done with microwave-based antigen retrieval methods. The Ki-67 index and the microvessel density were counted using an image analysis system. Maspin expression was positive in 75.5% of adenocarcinomas and 91.7% of adenomas. Only 47.1% of the nodal metastasis showed positive maspin expression. In colonic adenocarcinomas, p53 expression was positive in 44.7% of the maspin-positive groups compared with 100% of the maspin-negative groups (P < 0.005). Colonic adenocarcinomas with the positive maspin expression groups showed less intense microvessel density (181.1 ± 54.2) than those of the negative maspin expression groups (256.1 ± 75.4, P < 0.001). In conclusion, we demonstrated maspin expression in colon cancer with a sequential decreased expression rate from adenoma to metastatic carcinomas, which signifies the tumor suppressive function of maspin, and an inverse correlation with p53 and microvesel density, which indicates the regulatory effect of p53 on maspin and anti-angiogenesis effect of maspin.