p33^ING1和p53基因蛋白在乳腺癌中的表达及其意义

目的 探讨p23ING1、p53基因蛋白在乳腺增生及乳腺癌中表达的意义及相互关系. 方法 应用Envision免疫组化法对正常乳腺组织、单纯增生、非典型增生、乳腺癌各50例标本进行p33ING1、p53基因蛋白表达检测. 结果 p33ING1蛋白在乳腺正常组织、单纯增生、非典型增生、乳腺癌中阳性表达率分别为100.0%(50/50)、100.0%(50/50)、96.0%(48/50)和62.0%(31/50),阳性表达逐渐下降;p53蛋白阳性表达率分别为0(0/50)、0(0/50)、24.0%(12/50)和54.0%(27/50),阳性表达率逐渐上升.非典型增生与正常组织相比,差异有显著性(P＜0.05);乳腺癌与正常组织相比,差异有非常显著性(P＜0.01). 结论 p33ING1阳性者p53阳性表达率远低于p33ING1阴性者,p33ING1与p53呈负相关.p33ING1和野生型p53基因都是抑癌基因,p33ING1是p53的分子伴侣.     

抑癌基因ING1、p21/WAF1、P53蛋白在胃癌中的表达

目的　研究ING1、p2 1 /WAF1、p53基因蛋白在胃癌组织中的表达意义及相互关系。方法　对 71例胃癌组织应用Envision免疫组化法 ,检测 p33ING1 、p2 1 /WAF1、p53的表达情况 ,分析其相关性 ,结合临床病理因素 ,探讨胃癌发生、进展及预后的关系。结果　p33ING1 与p2 1 /WAF1、p53表达有相关性 (P <0 .0 5) ,p33ING1 表达率为 62 .0 % (44/71 ) ,与正常组织相比呈低表达 ,与胃癌的浸润、淋巴结转移、远隔转移、分化程度有相关性 (P <0 .0 1 ) ;p2 1 /WAF1表达率为54 .9% (39/71 ) ,与胃癌浸润相关 (P <0 .0 5) ;p53表达为 63 .4 % (45/71 ) ,与浸润及淋巴结转移相关 (P <0 .0 1 )。结论　ING1是抑癌基因 ,其蛋白p33ING1 在胃癌中低表达 ,对胃癌的发生、发展可能起重要作用 ,p33ING1 、p2 1 /WAF1、p53表达可作为判断胃癌恶性程度及预后的重要指标     

p33~(INGI)、p53在结直肠癌中的表达及其相互关系

目的:探讨p33ING1、p53在结直肠癌中的表达及其相互关系。方法:应用免疫组化SP法检测60例结直肠癌组织及相应正常黏膜组织中p33ING1、p53的表达。结果:结直肠癌组织、相应正常黏膜组织中p33ING1蛋白的阳性表达率分别为43．3％(26／60)、100％(60／60)(P<0．01),p53蛋白分别为51．6％(31／60)、0％(0／60)。p33ING1在无淋巴结转移组及淋巴结转移组癌组织中的阳性表达率分别为57．6％(19／33)、25．9％(7／27)(P<0．05);在Dukes A、B期、Dukes C、D期病例中分别为56．7％(17／30)、30．0％(9／30)(P<0．05)。在p53表达阴性的29例中有12例(41．4％,12／29)p33ING1表达缺失,而p53阳性的31例病例中有22例(71．0％,22／31)p33ING1表达阴性(P<0．05),在p53蛋白表达阳性的病例中p33ING1蛋白表达明显缺失,两者表达呈负相关。结论:p33ING1在结直肠癌组织中低表达,与p53互相协同,在结直肠癌的发生、发展中可能起重要作用。     

Expression of the novel tumour suppressor p33(ING1)is independent of p53

A recently cloned tumour suppressor candidate, p33ING1, has been shown in vitro to collaborate with p53 to execute growth arrest and apoptosis. However, it is unclear as to how the expression of ING1 is regulated in normal and stress conditions. Using a p53-knockout mouse model, we investigated if the expression of ING1 was dependent on p53. We found that there was no difference in ING1 mRNA and protein levels between p53+/+ and p53-/- murine organs. In addition, when normal human epithelial keratinocytes (NHEK) and a keratinocyte cell line, HaCaT, which lacks wild-type p53 function, were exposed to UVB irradiation, the expression levels of ING1 were elevated in both NHEK and HaCaT cells. It is interesting, however, that UVB irradiation did not induce ING1 expression in dermal fibroblasts isolated from p53+/+ and p53-/- mice. Based on our findings, we therefore conclude that the expression of ING1 is independent of p53 status. UV induction of ING1 in keratinocytes suggests that ING1 may play a role in cellular stress response and skin carcinogenesis.     

The tumor suppressor p33ING1b enhances taxol-induced apoptosis by p53-dependent pathway in human osteosarcoma U2OS cells

p33ING1b can stimulate cell cycle arrest, DNA repair, apoptosis and chemosensitivity. The actions of p33ING1b involve p53-dependent and p53-independent mechanisms. To investigate if the p33ING1b isoform is involved in the chemosensitivity of osteosarcoma cells, p33ING1b was overexpressed in p53+/+ U2OS cells or p53-mutant MG63 cells, and then cell growth arrest and apoptosis were assessed after treatment with taxol. The results showed that p33ING1b markedly increased taxol-induced growth inhibition and apoptosis in p53+/+ U2OS cells, but not in p53-mutant MG63 cells. Moreover, ectopic expression of p33ING1b could obviously upregulate p53, p21WAF1 and bax protein levels and activate caspase-3 in taxol-treated U2OS cells. Taken together, our data demonstrate that p33ING1b enhances taxol-induced apoptosis through p53-dependent pathway in human osteosarcoma cells. p33ING1b may be an important marker and/or therapeutic target in the prevention and treatment of osteosarcoma.     

ING1 and p53 tumor suppressor gene alterations in adenocarcinomas of the esophagogastric junction

The aim of this study was to characterize molecular alterations of the recently reported candidate tumor suppressor gene, ING1, and to explore the relationship between ING1 and p53 in a well-defined series of adenocarcinomas of the esophagogastric junction (AdEGJ). Polymerase chain reaction (PCR)-based assays were used to characterize ING1 and p53 alterations, relative to histologically normal esophageal mucosa. Two tumors were found to have ING1 mutations: one novel missense mutation (AGC(Ser)-->ATC(Ile)) at codon 147, and one silent mutation (TCG(Ser)-->TCA(Ser)) at codon 173. Reduced expression of the two major alternatively spliced ING1 messenger RNA variants, p47(ING1a) and p33(ING1b) was variable, but was reduced (1.2-10-fold) in 12 of 19 AdEGJs compared to normal esophageal epithelium. No association between p53 and ING1 alterations was apparent. We conclude that reduced ING1 expression is frequently associated with AdEGJ tumorigenesis, further supporting its role as a tumor suppressor gene, and that ING1 expression is independent of p53 status.     

Dysfunction of p53 pathway in human colorectal cancer: analysis of p53 gene mutation and the expression of the p53-associated factors p14ARF, p33ING1, p21WAF1 and MDM2

Mutations of p53 tumor suppressor gene increase with tumor progression in colorectal cancers. In this study, we examined the expressions of p33ING1, p14ARF, MDM2 and p21WAF1 mRNA in 25 advanced colorectal cancers by quantitative RT-PCR method, and compared the expression levels of p33ING1, p14ARF, p21WAF1 and MDM2 in relation to p53 status in the tumors. Fifteen of 25 colorectal cancers (60%) showed abnormal accumulation of p53 protein in the nucleus, and the remaining 10 colorectal cancers (40%) were negative for p53 immunostaining. We found a G --> T transition (nonsense mutation) at the first nucleotide of codon 298 (exon 8) in one p53-negative case, and a frame shift mutation on exon 7 in another p53-negative case. In remaining eight p53-negative cases, there was no mutation in the entire open reading frame of p53 cDNA. Interestingly, in eight cases with p53 wild-type gene, 6 cases (75%) showed a marked down-regulation of p14ARF mRNA, and three cases (37.5%) over-expressed MDM2 mRNA. Only one case with wild-type p53 gene showed normal level expression of p53 regulatory-factors (p33ING1, p14ARF, and MDM2). Thus, p53 tumor suppressor pathway was disrupted in 24 of 25 colorectal cancers (96%).     

Dysfunction of the p53 tumor suppressor pathway in head and neck cancer

It is important to examine the abnormality of the entire p53 tumor suppressor pathway in head and neck cancer. We examined the mRNA expressions of p53 regulatory factors, p33ING1 and p14ARF, and a p53-target gene, p21WAF1 in head and neck cancer. Nine of 14 benign pleomorphic adenomas (PAs) and 7 of 8 malignant salivary gland tumors (MSGTs) expressed p33ING1 mRNA. Thirteen of 14 PAs expressed p14ARF mRNA, however, only 1 of 8 MSGTs expressed p14ARF mRNA. Eight of 14 PAs and 7 of 8 MSGTs expressed p21WAF1 mRNA. In salivary gland tumors, there was clear correlation between the expression of p33ING1 and p21WAF1 (p<0.0001, r2=0.53). However, there was no correlation between the expression of p14ARF and p21WAF1 (p=0.6543, r2=0.009). Twenty-six of 28 oral squamous cell carcinomas (SCCs) expressed p33ING1 mRNA. Nineteen of 28 oral SCCs expressed p14ARF mRNA. All of the oral SCCs expressed p21WAF1 mRNA. In oral SCCs, the expressions of both p33ING1 (p=0.009, r2=0.181) and p14ARF (p=0.0009, r2=0.271) correlated with the expression of p21WAF1. Interestingly, 24 of 26 oral SCCs (92%) showed either abnormality of p53 itself or loss of expression of p53 regulatory factors, p33ING or p14ARF. These results suggest that head and neck cancer often involve the dysfunction of p53 tumor suppressor pathway.     

p33ING1b对鼻咽癌细胞HNE1增殖的影响

背景与目的：作为ING1的一种主要表达产物，p33^ING1b蛋白结合和稳定p53后诱导肿瘤细胞周期阻断或引起细胞凋亡。本研究通过建立高表达p33^ING1b的鼻咽癌细胞HNE1模型，探讨p33^ING1b对鼻咽癌细胞增殖影响及分子作用机制。方法：利用脂质体介导转染HNE1细胞，RT—PCR法筛选p33^ING1b高表达的阳性克隆，绘制生长曲线检测细胞增殖速度，免疫组化法检测细胞中p53的表达分布，流式细胞术检测细胞周期，Western blot法检测p53、p21、Stat3、C-myc和Cyclin D1蛋白水平。结果：转染ING1后p33^ING1b表达水平显著升高，HNE1细胞增殖能力受到抑制，出现G0／G1期的阻滞、S期比例下降。细胞中Stat3、C—myc和CyclinD1表达水平显著降低，p53与p21表达水平上升。结论：p33^ING1b可能通过促进HNE1细胞中p53和阻断Stat3两种不同信号传导通路抑制鼻咽癌细胞的增殖。     

Adenovirus-mediated transfer of p33ING1 with p53 drastically augments apoptosis in gliomas.

The p53 tumor suppressor gene is an important target for the gene therapy of cancers, and clinical trials targeting this gene have been conducted. Some cancers, however, are refractory to p53 gene therapy. Therefore, it has been combined with other therapies, including chemotherapy and radiotherapy, to enhance the cytopathic effect of p53 induction. The p33ING1 gene cooperates with p53 to block cell proliferation. In this study, we investigated whether adenovirus (Adv)-mediated coinduction of p33ING1 and p53 enhances apoptosis in glioma cells (U251 and U-373 MG), which showed no genetic alterations but low expression levels of p33ING1. Although the single infection of Adv for p33ING1 (Adv-p33) at a multiplicity of infection (MOI) of 100, or Adv for p53 controlled by myelin basic protein (MBP) promoter (Adv-MBP-p53), a glioma-specific promoter, at a MOI of 50, did not induce apoptosis in U251 and U-373 MG glioma cells; coinfection of Adv-p33 and Adv-MBP-p53 at the same MOIs induced drastically enhanced apoptosis in both cell lines. Apoptosis was not induced in NGF-treated PC-12 cells infected with a high MOI (300) of Adv-p33 nor in those coinfected with Adv-p33 (100) and Adv-MBP-p53 (50). Coinfection of Adv-p33 and Adv-MBP-p53 demonstrated morphological mitochondrial damage during the initial stage of apoptosis, which likely led to apoptotic cell death. Our results indicate that this coinfection approach can be used as a modality for the gene therapy of gliomas, sparing damage to normal tissues.     

Epigenetic and genetic alterations of p33ING1b in ovarian cancer

p33ING1b is a candidate tumor suppressor gene and a nuclear protein. We investigated whether genetic and epigenetic mechanisms affect p33ING1b expression in ovarian cancer thus contributing toward its pathogenesis. A total of 111 ovarian cancers collected from Beijing and Hong Kong were used for this study. Weak or negative p33ING1b protein expression was demonstrated by immunohistochemistry on tissue microarray in 28/111 cases. Real-time quantitative RT-PCR also showed overall significant reduction of p33ING1b mRNA expression (P = 0.0137), with 53.1% (17/32) cases showing 2- to 5-fold reduction and absence of expression. The reduction of mRNA expression in cancer correlated with decreased p33ING1b protein expression (P < 0.0001). While no p33ING1b mutation was found, allelic loss at the p33ING1b locus was demonstrated in 25% (8/32) cases. The allelic loss profiles also showed statistical significant correlation with reduction of p33ING1b protein and mRNA expression (P = 0.031 and 0.030). Promoter methylation as assessed by methylation specific PCR was found in 23.9% (21/88) cases analyzed. Bisulfite sequencing results confirmed the p33ING1b promoter methylation status of these methylation positive cases. Statistical significant correlation between methylation and mRNA expression (P = 0.006) was demonstrated. Treatment with demethylating drug, 5'-aza-2'-deoxycytidine, resulted in dosage-dependent elevated mRNA expression of p33ING1b in ovarian cancer cell lines. This is the first study reporting epigenetic mechanism regulating the p33ING1b expression. Our findings support that genetic and epigenetic alteration of p33ING1b are likely to contribute towards the pathogenesis of ovarian cancers.     

P33ING1、p53在膀胱移行细胞癌中的表达及与细胞凋亡的相关性

目的：探讨抑癌基因P33ING1在膀胱移行细胞癌（BTCC）中的表达及其与p53蛋白表达及细胞凋亡的相关性。方法：利用免疫组化S-P法和TUNEL法检测83例BTCC及11例正常膀胱黏膜组织P33ING1、p53的表达及细胞凋亡指数（AI）。结果：83例膀胱移行细胞癌组织中,P33ING1蛋白的阳性表达率为59.03%,而正常膀胱黏膜组织中P33ING1蛋白阳性表达率为90.9%。P33ING1蛋白表达与膀胱移行细胞癌的WHO肿瘤分级有相关性。Spearman相关分析表明P33ING1蛋白表达与p53蛋白表达正相关（P〈0.05）。AI与P33ING1及p53蛋白表达无相关性。结论：P33ING1在膀胱移行细胞癌中表达下降可能在膀胱移行细胞癌的发生、发展过程中起重要作用,P33ING1与p53基因具有协同作用,同时检测p53的状态和P33ING1表达水平,对于膀胱癌的诊断、治疗和预后判断可能具有积极意义。     

The tumor suppressor candidate p33(ING1) mediates repair of UV-damaged DNA.

The biological functions of the tumor suppressor, ING1, have been studied extensively in the last 5 years since it was cloned. It shares many biological functions with those of p53 and has been reported to mediate growth arrest, senescence, apoptosis, anchorage-dependent growth, and chemosensitivity. Some of these functions, such as cell cycle arrest and apoptosis, have been shown to be dependent on the activity of both ING1 and p53 proteins. In this study, we report that p33(ING1) (one of ING1 isoforms) is also involved in the modulation of DNA repair. We found that overexpression of p33(ING1) enhances repair of UV-damaged DNA and that p53 is required for the repair process. Furthermore, binding between ING1 and GADD45 has been detected. These observations suggest that p33(ING1) cooperates with p53 in nucleotide excision repair and that GADD45 may be one of its components.