转染P53基因对胶质瘤细胞株SHG44裸鼠致癌性的作用研究

 目的:探讨转染野生型P⁵³(wt-P⁵³)和突变型P⁵³(mtP⁵³)基因,对人胶质瘤细胞株SHG44裸鼠致瘤性的影响及意义.方法:采用质脂体介导法,分别将wt-P⁵³和mt-P⁵³基因导入人胶质瘤细胞株SHG44,体内外检测转导细胞的生长状况和裸鼠致瘤性.结果:转染mt-P⁵³基因的细胞株,G418筛选细胞集落数、软琼脂平皿细胞集落数以及裸鼠瘤组织重量和体积,均显著高于对照组(P <0.01);而转染Wt-P⁵³ 基因的细胞株均显著低于对照组(P<0.01),表明导入wt-P⁵³基因的细胞株,瘤细胞生长速度明显低于对照细胞株和导入.mt-P53基因的细胞株,即导入mt-P⁵³基因的细胞株瘤细胞生长速度最快,而导入Wt-P⁵³基因的细胞株瘤细胞生长速度最慢.结论:Wt-P⁵³基因能有效地抑制人胶质瘤细胞生长;mt-P⁵³基因则可以明显地促进瘤细胞生长.     

PCR-SSCP法检测宫颈癌P53基因突变

 目的：探讨抑癌基因P⁵³突变与宫颈癌发生发展之间的关系,并为该病的临床检测提供一种分子生物学方法。方法：应用多聚酶链反应－单链构象多态性（PCR SSCP）分析方法对宫颈癌及慢性宫颈炎组织中P⁵³基因5～6外显子的突变进行了检测。结果：35例宫颈癌组织中有2例出现突变,突变率为5.71%;而作为对照的慢性宫颈炎组织中无一例出现突变。结论：宫颈癌的发生与抑癌基因P⁵³5～6外显子的突变有关;此方法可有效地检测抑癌基因P⁵³的突变。     

P53突变产物在睑板腺癌中的增强表达及其意义

 我们采用免疫组化S-P法, 对17例石蜡包埋睑板腺癌及癌旁组织标本的P⁵³突变蛋白表达进行了检测。 结果:17例癌组织有12例表达阳性, 阳性率71%。其中分化型7例, 6例呈阳性(86%)表达。在一组原发灶及淋巴结转移癌配对标本中, 同一病人之两个部位P⁵³突变蛋白表达差异无明显意义。 癌旁(睑缘)组织17例中5例上皮有异常增生, 且同时伴有P⁵³突变蛋白呈强阳性表达。 以上结果提示:抑癌基因P53的突变在睑板腺癌的发生中是一个比较常见的基因改变, 且在分化型癌的发生中表现明显; P⁵³基因异常发生在肿瘤转移之前且在淋巴道转移中可能起重要作用; P⁵³突变蛋白在癌旁上皮异型增生组织中的过度表达具有十分重要的意义。     

西南地区原发性肝癌抗癌基因P53点突变的研究

 本文采用PCR－RFLP技术对西南地区原发性肝细胞癌P⁵³基因第248和249位密码子点突变进行了研究。约17．4%的肝癌存在第249位密码子点突变。没有发现248位密码突变。本研究结果提示癌基因P⁵³点突变在该地区肝癌发病中起有一定作用；西南地区肝癌的发生可能有AFB1的参与。     

P53、P16蛋白在卵巢上皮癌中的表达

 目的:探索抑癌基因P⁵³、P¹⁶表达与卵巢上皮癌发生的关系。方法:采用免疫组化SP法对27例卵巢上皮癌组织中P⁵³蛋白,P¹⁶蛋白进行检测。结果:卵巢上皮癌P⁵³蛋白阳性表达率为44.44%。P¹⁶蛋白在卵巢上皮癌中表达阳性率为18.52%,P⁵³及P¹⁶表达与病理类型无关。P⁵³蛋白过度表达与临床分期无关。P¹⁶晚期表达阳性率明显减少(P<0.05)。结论:P⁵³、P¹⁶基因表达的改变在卵巢上皮癌发生中起重要的作用。     

直肠癌P21、P53基因表达及其临床意义

 目的: 研究P²¹、P⁵³基因在直肠癌组织中的表达情况与直肠癌病理特征的关系及其在预后判定方面的意义。方法: 采用SP免疫组化法对110例手术后石蜡包埋标本行P²¹、P⁵³基因表达检测, 同时选用正常组织为实验对照。结果: 直肠癌组织P²¹、P⁵³基因表达阳性率分别为54.5 %、42.7 %;P53组织表达情况与临床病理因素无相关性; P²¹表达阳性病例3 、5年生存率降低, 组 织分化差, 淋巴转移率增高(P<0.05 %)。结论: P⁵³基因与直肠癌形成密切相关, 与直肠癌预后未见相关性。P²¹基因表达情况可能成为直肠癌的预后指标。     

有和无内分泌分化大肠癌P53和表皮生长因子受体表达的比较研究

 目的：研究大肠癌内分泌分化与P⁵³表皮生长因子受体（EGFR）表达的关系及意义。方法：采用免疫组织化学ABC法，检测79例大肠癌手术切除组织中嗜铬蛋白A（CGA），P⁵³及EGFR的表达变化。结果：大肠癌组织中CGA，P⁵³及EGFR的表达率分别为：35.4％（28/79〕，60.8％(48/79）和30.4％（24/79），有内分泌分化的大肠癌P⁵³表达率及其免疫阳性细胞数分别为78.6％（22/28）和984.3士702.0/mm²，无内分泌分化者分别为51.0％和589.5士489.5/mm²，前者明显高于后者（P53及EGFR的表达明显高于无内分泌分化者，提示P⁵³及EGFR的表达可能与大肠癌的内分泌分化有关     

小儿非何杰金淋巴瘤P53基因突变与预后的研究

 目的: 探讨小儿非何杰金淋巴瘤(NHL)P⁵³基因突变与预后的关系。方法: 31例颈部与腹部Ⅱ、Ⅲ期NHL 患儿, 应用PCR-SSCP技术检测石腊标本中P⁵³基因第5-6外显因子, 并对31例患者进行了近8年的随访。结果: 31例中11例存在着P⁵³基因突变, 此11例中有7例复发。而无P⁵³基因突变20例中仅1例复发。结论: 说明小儿NHL中P⁵³基因突变是不良预后的指标, 与早期复发有关。     

突变型P53在甲状腺肿瘤中的表达及意义的研究

 P⁵³基因的突变或缺失是许多肿瘤发生的原因.甲状腺癌的发生发展与癌基因,抑癌基因的异常调控密切相关.     

消癌解毒方抑制肝癌H22移植瘤的生长及其机制

目的:研究消癌解毒方(Xiaoai Jiedu Recipe,XJR)对肝癌H22细胞小鼠移植瘤的抑制作用及其可能的机制。方法:建立小鼠H22移植瘤模型,分对照组和XJR低、中、高剂量(10、30、90g/kg)组及顺铂(0.001g/kg)组进行治疗,检测各组移植瘤生长情况,H-E染色观察各组移植瘤组织的病理改变。流式细胞术检测各组移植瘤细胞周期及凋亡率,ELISA法测定各组移植瘤小鼠外周血VEGF水平。结果:与对照组比较,XJR各剂量以及顺铂对H22移植瘤的生长均具有显著的抑制作用,抑瘤率分别为24.5%、42.8%、21.1%、58.6%(P<0.05或P<0.01)。病理观察见中剂量XJP组和顺铂组移植瘤组织大片状坏死,有明显染色质固缩环。中剂量XJR和顺铂将移植瘤组织细胞阻滞于G0/G1期(P<0.05),S期细胞数明显减少(P<0.05)。中剂量XJR组移植瘤细胞的凋亡率与顺铂组相当[(60.52±6.40)%vs(71.32±16.02)%,P>0.05]。中、高剂量XJR组和顺铂组小鼠外周血VEGF水平均显著降低[(104.3±6.1)、(105.8±7.2)、(88.6±4.3)vs(120.7±12.6)ng/ml,P<0.05或P<0.01]。结论:XJR能抑制H22小鼠移植瘤的生长,促进移植瘤细胞凋亡、抑制VEGF的产生可能是其抗癌作用机制之一。     

In primary human breast carcinomas mutations in exons 5 and 6 of the p53 gene are associated with a high s-phase index

A series of 121 human breast tumors was screened for point mutations in exons 5 through 8 of the p53 gene, by SSCP analysis. On the same tumor samples, the S-phase index (SPI) was determined by the incorporation of BUdR in fresh tissue. p53 mutations were observed in 29% of the cases. The frequency of point mutations for the individual exons was: exon 5, 10.0%; exon 6, 9.9%; exon 7, 7.1% and exon 8, 5.5%. Two mutations detected by SSCP were confirmed by sequencing the p53 cDNA. The presence of a p53 mutation, irrespective of its location, correlates (p = 0.003) with a high SPI. This association appears to primarily reflect mutations in exon 5 (p = 0.0002) and exon 6 (p = 0.05), since mutations in exons 7 and 8 failed to show any association. These results indicate that mutations in the p53 gene identify highly proliferating tumors, and that the position of the p53 mutation may have different effects upon the proliferative activity of tumor cells in vivo.     

Use of the single strand conformation polymorphism technique and PCR to detect p53 gene mutations in small cell lung cancer.

Recent studies have suggested that the p53 oncoprotein might function normally as a tumor suppressor. Mutations in highly conserved regions of the p53 gene have been observed in numerous types of tumors and tumor cell lines. To detect in a more sensitive manner p53 gene mutations in small cell lung cancer (SCLC) we utilized the single strand conformation polymorphism (SSCP) technique of Orita et al., (1989). Using PCR primers for the most highly conserved regions of the p53 gene, including exons 4-9, we have identified p53 mutations in 5 of 9 small cell lung cancer (SCLC) tumor DNA samples and in 1 SCLC cell line. None of the mutations seen in tumor DNA samples were present in normal DNA from the same patients, indicating that mutation of the p53 gene in these tumors was a somatic event. Of the six mutations observed, two were found in exon 7, three were found in the region encompassing exons 8 and 9, and one was found in the region encompassing exons 5 and 6. Nucleotide sequencing of one of the exon 7 mutations and one of the exon 8-9 mutations indicated that each was a C to T transition. In SCLC-6 the mutation resulted in substitution of serine for proline at amino acid 278 and in SCLC-4 substitution of tryptophan for arginine at amino acid 248, both nonconservative amino acid substitutions. Both of these changes are in regions of the p53 gene where mutations have been observed in other tumors. Two additional mutations were observed in SCLC cell lines using conventional PCR techniques. One of these is a mutation which results in altered splicing of the p53 pre-mRNA.     

P~(53)基因突变及P~(53)突变蛋白在卵巢上皮肿瘤中表达检测方法的探讨

采用改进的ａＰＣＲ－ＳＳＣＰ银染技术和ＳＰ免疫组化技术检测３６例卵巢上皮癌，１２例卵巢上皮交界瘤和１５例良性卵巢上皮肿瘤的Ｐ５３基因的突变和突变蛋白的表达。结果卵巢上皮癌Ｐ５３基因突变率为３０．６％，突变蛋白表达为５８．４％。Ｐ５３基因突变主要发生在外显子５～８上，以第７外显子突变率最高。交界性肿瘤个别出现Ｐ５３基因突变和突变蛋白表达，而在良性肿瘤无一例出现。提示Ｐ５３基因突变是卵巢癌形成过程中的晚期事件。Ｐ５３基因突变可作为肿瘤标记物判定卵巢癌的预后。ａＰＣＲ－ＳＳＣＰ非同位素基因突变技术克服了常规ＰＣＲ－ＳＳＣＰ检测方法的缺陷，可提高准确性。     

Inactivation of the INK4A/ARF locus frequently coexists with TP53 mutations in non-small cell lung cancer

Inactivation of the P16 (INK4A)/retinoblastoma (RB) or TP53 biochemical pathway is frequent event in most human cancers. Recent evidence has shown that P14ARF binds to MDM2 leading to an increased availability of wild type TP53 protein. Functional studies also support a putative tumor suppressor gene function for p14ARF suggesting that p14ARF or p53 inactivation may be functionally equivalent in tumorigenesis. To study the relative contribution of each pathway in tumorigenesis, we analysed and compared alterations of the p16, p14ARF and p53 genes in 38 primary non-small cell lung cancers (NSCLCs) (19 adenocarcinomas and 19 squamous carcinoma). The p16 tumor suppressor gene was inactivated in 22 of 38 (58%) tumors. Twelve of these samples (31%) had homozygous deletions by microsatellite analysis; eight of them (21%) had p16 promoter hypermethylation detected by Methylation Specific PCR (MSP) and the remaining two (5%) harbored a point mutation in exon 2 by sequence analysis. The absence of P16 protein in every case was confirmed by immunohistochemistry. Fourteen of the 22 tumors with p16 inactivation also inactivated the p14ARF gene (12 with homozygous deletions extending into INK4a/ARF and two with exon 2 mutations). Mutations of p53 were found in 18 (47%) of the tumors and nine of them (50%) harbored p14ARF inactivation. Thus, an inverse correlation was not found between p14ARF and p53 genetic alterations (P=0.18; Fisher Exact Test). Our data confirm that the p16 gene is frequently inactivated in NSCLC. Assuming that 9p deletion occurs first, the common occurrence of p53 and p14ARF alterations suggests that p14ARF inactivation is not functionally equivalent to abrogation of the TP53 pathway by p53 mutation.     

PTEN/MMAC1 mutations in hepatocellular carcinomas.

Mutations in the PTEN/MMAC1 gene have been identified in several types of human cancers and cancer cell lines, including brain, endometrial, prostate, breast, thyroid, and melanoma. In this study, we screened a total of 96 hepatocellular carcinoma (HCC) samples from Taiwan, where HCC is the leading cancer in males and third leading cancer in females, for mutations in the PTEN/MMAC1 gene. Complete sequence analysis of these samples demonstrated a missense mutation in exon 5 (K144I) and exon 7 (V255A) from HCC samples B6-21 and B6-2, respectively. A putative splice site mutation was also detected in intron 3 from sample B6-2. Both B6-21 and B6-2 were previously shown to contain missense mutations in the coding sequences of the p53 gene. Functional studies with the two missense mutations demonstrated that while mutation V255A in exon 7 resulted in a loss of phosphatase activity, mutation K144I in exon 5 retained its phosphatase activity. Additionally, we identified a silent mutation (P96P) in exon 5 of the PTEN/MMAC1 gene from HCC sample B6-22. These data provide the first evidence that the PTEN/MMAC1 gene is mutated in a subset of HCC samples.     

结直肠癌患者血清及粪便中P53基因检测的临床意义

背景与目的：研究大肠癌患者血清P53-Ab、粪便P53基因突变与癌组织中P53蛋白表达之间关系，以探讨P53基因在大肠癌发生与早期诊断中的作用及临床意义：材料与方法：运用酶联免疫吸附分析（Enzyme-linked immunosorbent assay，ELISA）法检测34例大肠癌患者及10例健康人血清P53-Ab，运用聚合酶链反应-单链构象多态性分析（Polymerase chain reactiotr-single strand conformation polymorphism，PCR-SSCP）分析16例大肠癌患者粪便P53基因第5～8外显子突变，同时运用PCR-SSCP与免疫组化法分析癌组织中P53基因突变及蛋白表达状况。结果：大肠癌中血清P53-Ab阳性率为17．6％，正常对照组为阴性。癌组织中P53基因突变率及蛋白表达率分别为52．9％和55．9％，正常黏膜未见P53基因突变及蛋白表达：16例P53基因突变的患者其粪便中基因突变率为43．8％。P53基因突变及蛋白表达与P53-Ab存在及临床病理冈素无关。结论：P53基因突变是参与和影响P53蛋白表达的主要因素，P53蛋白表达可诱导P53-Ab产生。大肠癌患者粪便中可枪测出P53基因突变，粪便P53基因及血清P53-Ab检测可有助于大肠癌的诊断及高危人群的筛检普查。     

肺腺癌p53基因突变与临床病理特征关系的研究

目的探讨p53基因在肺腺癌中突变的频率、位置和在肺腺癌发生发展中的作用及与其临床病理特征的关系。方法聚合酶链式反应一单链构象多态性（PCR－SSCP）检测31例肺腺癌的P53基因第5～8外显子突变。结果14例（45％）出现P53基因5～8外显子突变，其中7、8外显子突变占73％。P53基因突变男性显著高于女性（P—0．003），在肿瘤≤3cm的病例p53基因突变率显著低于肿瘤＞3cm的病例（P=0．005）。p53基因突变与吸烟史、年龄、组织学类型、分化程度、淋巴结状况、国际病理TNM分期及瘤栓无显著性差异（P＞0．05）。结论肺腺癌中P53突变率为45％，主要分布在第7、8外显子，P53基因突变参与肺腺癌癌变的始动和腺癌的进展。     

High frequency and heterogeneous distribution of p53 mutations in aflatoxin B1-induced mouse lung tumors.

Inactivation of the p53 tumor suppressor gene is one of the most frequent genetic alterations observed in human lung cancers. However, p53 mutations are more rarely detected in chemically induced mouse lung tumors. In this study, 62 female AC3F1 (A/J x C3H/HeJ) mice were treated with aflatoxin B1 (AFB1; 150 mg/kg i.p. divided into 24 doses over 8 weeks). At 6-14 months after dosing, mice were killed, and tumors were collected. A total of 71 AFB1-induced lung tumors were examined for overexpression of p53 protein by immunohistochemical staining. Positive nuclear p53 staining was observed in 79% of the AFB1-induced tumors, but the pattern was highly heterogeneous. In approximately 73% of the positively stained tumors, fewer than 5% of cells demonstrated positive staining; in the other 27%, between 10% and 60% of the cells stained positively, with staining localized to the periphery of the tumors in many cases. Single-strand conformational polymorphism analysis of the evolutionarily conserved regions of the p53 gene (exons 5-8) from AFB1-induced whole lung tumor DNA revealed banding patterns consistent with point mutations in 20 of 76 (26%) tumors, with 85% of the mutations in exon 7 and 15% of the mutations in exon 6. Identification of point mutations could not be confirmed by direct sequence analysis because bands representing putative mutations appeared only weakly on autoradiograms. This was presumably due to the heterogeneous nature of the DNA analyzed. Single-strand conformational polymorphism analysis of DNA from laser capture microdissected cells of paraffin-embedded AFB1-induced tumor tissue sections stained for p53 produced banding patterns consistent with point mutations in 18 of 30 (60%) DNA samples. Direct sequencing of the microdissected samples revealed mutations at numerous different codons in exons 5, 6, and 7. Of 26 mutations found in microdissected regions from adenomas and carcinomas, 9 were G:C-->A:T transitions, 11 were A:T-->G:C transitions, and 5 were transversions (2 G:C-->T:A, 2 T:A-->A:T, and 1 A:T-->C:G), whereas 1 deletion mutation was identified. The concordance between immunostaining and molecular detection of p53 alterations was 72% when laser capture microdissection was used versus 17% based on whole tumor analysis. The high mutation frequency and heterogeneous staining pattern suggest that p53 mutations occur relatively late in AFB1-induced mouse lung tumorigenesis and emphasize the value of analyzing different staining regions from paraffin-embedded mouse lung tumors.     

Characterization of p53 gene mutations in esophageal squamous cell carcinoma cell lines: Increased frequency and different spectrum of mutations from primary tumors

We screened 29 human esophageal squamous cell carcinoma (ESC) cell lines for mutations of the p53 gene through all coding exons and exon—intron junctions. Mutations were found in 22 cell lines (76%), consisting of 20 single-base substitutions, 2 small deletions and 1 single-base insertion. Out of 20 single-base substitution, 5 were located at the exon—intron junctions and mRNAs with abnormal splicing were detected by RT-PCR in 4 of them. A G:C to T:A transversion, which occurred rather frequently in resected tumors of ESC, was observed in only 1 cell line, and, instead, frequent transitions at CpG sites were detected. We also examined 65 fresh tumor materials, from all of which we tried to establish cell lines, and detected mutations in 26 samples (40%). Compared with the results in these fresh tumor materials, the mutation incidence in cell lines was significantly high and the mutation spectrum was also different. From these 65 tumors, 10 cell lines were established, including 3 cell lines from 26 tumors with p53 mutations and 7 cell lines from 39 without mutations, which indicates that there was no significant correlation between the status of the p53 gene in each fresh tumor and its establishment as a cell line. In 7 cell lines established from mutation-free tumors, newly acquired mutations were detected in 5, which suggests that mutations might occur during the process of establishing cell lines. © 1996 Wiley-Liss, Inc.     

Heterogeneous distribution of P53 immunoreactivity in human lung adenocarcinoma correlates with MDM2 protein expression, rather than with P53 gene mutation

Although the tumor suppressor p53 protein (P53) immunoreactivity and its gene (p53) mutation were reported to be significant prognostic indicators for human lung adenocarcinomas, little is known regarding the relationship between the heterogeneous distribution of P53 and its genetic status in each tumor focus and the clinicopathological significance. To determine how P53 is heterogeneously stabilized in patients, we compared P53 expression to both the p53 allelic mutation in exon 2 approximately 9 by polymerase chain reaction-single strand conformation polymorphism using microdissected DNA fractions, and the immunohistochemical MDM2 expression. Of the 48 positive to P53 in 118 lung adenocarcinomas examined, 10 with heterogeneous P53 expression were closely examined. The higher P53 expression foci in 7 of 10 cases were less differentiated, histologically in respective cases, and were frequently associated with fibrous stroma. Two had genetic mutations in exon 7 of the p53 gene in both the high and low P53 expression foci of cancer tissue indicating no apparent correlation between heterogeneous P53 expression and the occurrence of gene mutation. Immunohistochemical expression of MDM2 was significantly lower in high P53 expression areas (p < 0.05, the mean labeling indices of high and low P53 expression areas being 4.2 +/- 5.4% and 13.6 +/- 12.2%, respectively). In addition, among all the 118 cases examined, MDM2 expression was significantly suppressed in cases of p53 gene mutation, simultaneously with P53 overexpression, as compared with cases without both the p53 mutation and expression (p < 0.001). These findings suggest that the heterogeneous stabilization of P53 in human lung adenocarcinomas could be partly due to suppressed MDM2 expression. The overexpression of non-mutated P53 may afford a protective mechanism in human lung adenocarcinomas.