Expression of the p53 Gene and Activation of p53-Dependent Transcription in Melanoma Cell Lines

Malignant melanoma has poor prognosis because of its high metastatic potential and resistance to chemotherapy. A possible approach to more effective therapy is induction of p53-dependent apoptosis. This approach is promising, since the wild-type _p53 is expressed in most melanomas. An attempt was made to estimate the functional activity of p53 in several malignant melanoma cell lines. Most lines were characterized by a high protein level and nuclear localization of p53. All cell lines expressing the wild-type p53 showed stabilization of p53, its translocation into the nucleus, and activation of several target genes in response to DNA-damaging agents, suggesting that p53 was functionally active. A high-molecular-weight protein localized in the cytoplasm and mimicking a p53 epitope was found in several cell lines. It was shown that the DO-1 epitope is not derived from p53, ruling out cytoplasmic retention of p53 in melanoma cell lines. A mechanism of camptothecin-induced stabilization of p53 by decreasing the level of the HDM2 mRNA was described for melanoma cells but not for normal melanocytes, suggesting a differential effect of camptothecin on tumor-derived and primary cells.__________Translated from Molekulyarnaya Biologiya, Vol. 39, No. 3, 2005, pp. 445–456.Original Russian Text Copyright © 2005 by Razorenova, Agapova, Chumakov.     

p53 Activates the Long Noncoding RNA Pvt1b to Inhibit Myc and Suppress Tumorigenesis

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磁免疫电化学发光检测肺癌血清p53抗体

肿瘤抑制基因——p53基因的突变可能产生p53抗体.p53抗体在肿瘤的诊断、预后及监测等方面具有重要的临床价值.目前检测p53抗体的方法,如酶联免疫分析方法,需要多个步骤,比较费时,且大部分检测指标只能是半定量,具有一定的局限性.提出了一种磁免疫电化学发光(IM-ECL)分析方法定量检测人血清p53抗体.这种新的分析方法检测人血清p53抗体的最低检测极限可达到10 ng/L,标准曲线的动力学范围和线性范围达到5个数量级（0.01～1 000 μg/L）.我们应用IM-ECL分析法检测肺癌病人血清,只需要50 μl的样品量,30 min的孵育时间和少于50 s的采集时间,得出肺癌血清中p53抗体的阳性率为28.6 ％,然后通过标准曲线定量阳性血清中p53抗体的浓度.从肺癌血清的结果中发现,随着临床分期的升高,p53抗体浓度增加.IM-ECL分析方法在检测限、线性范围、分析时间等方面都优于酶联免疫分析,是一种可行的快速、灵敏、定量检测人血清p53抗体的分析方法.     

ASSP在非小细胞肺癌中的表达及与预后关系

目的:研究ASPP蛋白在非小细胞肺癌中的表达情况,探讨其表达与患者预后之间的关系。方法:选取于我院就诊的86例非小细胞肺癌患者,病理学诊断癌症分型及分期,对所有患者进行随访,并用免疫组化法检测患者组织切片中ASPP2、i ASPP和p53的表达,SPSS软件分析ASPP2、i ASPP表达水平与患者预后的关系。结果:NSCLCⅢ期的患者中ASPP2阳性表达的中位生存期大于阴性患者,i ASPP阴性表达患者的中位生存期大于阳性患者(P0.05);p53野生型Ⅲ期患者ASPP2阳性表达者的中位生存期显著大于阴性表达患者,Ⅰ、Ⅲ期i ASPP阴性表达患者的中位生存期显著大于阳性表达患者义(P0.05)。p53突变型患者Ⅲ期iASPP阴性表达患者的中位生存期显著大于阳性表达患者(P0.05)。ASPP2和i ASPP蛋白的表达水平和治疗方式均为影响患者预后的因素(P0.05)。结论:ASPP2的阳性表达和i ASPP的阴性表达是NSCLC的保护因素,可在一定程度上预测患者的生存期。     

Nucleolar protein GLTSCR2 stabilizes p53 in response to ribosomal stresses

p53 is a key regulator of cell growth and death by controlling cell cycle progression and apoptosis under conditions of stress such as DNA damage or oncogenic stimulation. As these processes are critical for cell function and inhibition of tumor development, p53 regulatory pathways are strictly monitored in cells. Recently, it was recognized that nucleolar proteins, including nucleophosmin/B23, ribosomal protein L11, and alternate reading frame (ARF), form the nucleolus-ARF-murine double minute 2 (MDM2) axis in p53 regulatory pathways, which increases p53 stability by suppressing the activity of MDM2. In this work, we show that nucleolar protein glioma tumor-suppressor candidate region gene 2 (GLTSCR2) translocates to the nucleoplasm under ribosomal stress, where it interacts with and stabilizes p53 and inhibits cell cycle progression without the involvement of the major upstream p53 regulator, ARF. Furthermore, ectopic expression of GLTSCR2 significantly suppressed growth of cancer cells in a xenograft animal model via p53-dependent pathway. Our data identify GLTSCR2 as a new member of the nucleolus-nucleoplasmic axis for p53 regulation. ARF-independent direct regulation of p53 by GLTSCR2 may be a key mechanism and therapeutic target for cell death or growth inhibition when nucleolus-ARF-p53 pathways are inactivated by genetic or epigenetic modifications of ARF, which are the second most common types of genetic change observed in human cancers.     

晚期非小细胞肺癌p53 和ERCC1 表达状态与顺铂为主的 联合方案化疗的近期有效率的相关性研究*

目的:研究晚期非小细胞肺癌不同的p53和ERCC1表达状态与基于顺铂为主的姑息化疗近期有效率的相关性。方法:对经顺铂联合多西他赛或顺铂联合吉西他滨治疗的48例晚期非小细胞肺癌患者进行回顾性分析,利用既往免疫组化资料,观察基于顺铂为主的方案近期有效率(RR)的影响因素及化疗不良反应。结果:全组48例患者均完成至少两周期化疗,并行疗效评价。该组患者化疗的近期有效率为28例(58.3%),RR与不同的转移病灶部位(P=0.042)及病灶数目(P=0.034)有显著差异。该类方案的近期有效率与ERCC1状态(P=0.012)密切相关,而与p53表达状态(P=0.401)无关。毒性反应主要是骨髓抑制、脱发及消化道反应等。结论:晚期非小细胞肺癌ERCC1阴性患者较ERCC1阳性患者运用顺铂为主的联合方案化疗的近期有效率较高。ERCC1可能是顺铂疗效预测的敏感因子。p53的表达状态可能不是该类方案的疗效预测因子。     

miR-126增加非小细胞肺癌细胞A549对顺铂的敏感性

miR-126在多种恶性肿瘤中存在表达下调并显示抑癌基因的功能,然而其在肿瘤敏感性中的作用仍不明确.为了探讨miR-126在非小细胞肺癌细胞A549对顺式铂氨(cis-diammine dichloroplatoum, cisplatin, CDDP)敏感性中的作用及可能机制,本研究用MTS法检测非小细胞肺癌细胞A549及其衍生的CDDP耐受细胞A549/DDP对CDDP的敏感性.结果表明,A549/DDP细胞对CDDP的耐受性是A549细胞的4.05倍(P=0.0078)|用qRT-PCR检测发现,相比于A549细胞,A549/DDP细胞中miR-126的表达下调了8.45倍(P=0.0063),而survivin和Bcl-2的表达明显上调|通过MTS、qRT-PCR及Western印迹实验发现,miR-126 mimics使A549/DDP细胞中miR-126的表达上调了12.63倍(P=0.0013),并明显增加A549/DDP细胞对CDDP的敏感性及下调survivin和Bcl-2的表达;相反,miR-126 inhibitor能明显增加A549细胞对CDDP的耐受性及增加survivin和Bcl-2的表达.本研究结果提示,miR-126在非小细胞肺癌CDDP耐受细胞中的表达下调,上调miR-126的表达能增加耐药细胞对CDDP的敏感性. miR-126是逆转肺癌CDDP耐受的可能潜在靶标.     

Expression and clinicopathological significance of lipin-1 in human breast cancer and its association with p53 tumor suppressor gene

Breast cancer (BC) is an important cause of female cancer-related death. It has recently been demonstrated that metabolic disorders including lipid metabolism are a hallmark of cancer cells. Lipin-1 is an enzyme that displays phosphatidate phosphatase activity and regulates the rate-limiting step in the pathway of triglycerides and phospholipids synthesis. The objective of this study was to evaluate lipin-1 expression, its prognostic significance, and its correlation with p53 tumor suppressor in patients with BC. In this study, 55 pairs of fresh samples of BC and adjacent noncancerous tissue were used to analyze lipin-1, using quantitative real-time polymerase chain reaction and immunohistochemistry (IHC) staining. The expression of other clinicopathological variables and p53 was also examined using IHC technique. The cell migration was studied in MCF-7 and MDA-MB231 cells following the inhibition of lipin-1 by propranolol. Our results show that the relative expression of lipin-1 messenger RNA was significantly higher in BC tissues compared with the adjacent normal tissue and its inhibition reduced cell migration in cancer cells. This upregulation was negatively correlated with histological grade of tumor and p53 status (p = .001 and p = .034) respectively and positively correlated with the tumor size (p = .006). Our results also seem to indicate that the high lipin-1 expression is related to a good prognosis in patients with BC. The expression of lipin-1 may be considered as a novel independent prognostic factor. The inhibition of lipin-1 may also have therapeutic significance for patients with BC. The correlation between lipin-1 and p53 confirms the role of p53 in the regulation of lipid metabolism in cancer cells.     

长链非编码RNA SNHG17通过抑制p57表达促进肺癌进展

目的:分析肺癌中长链非编码RNA(lncRNA)小核仁RNA宿主基因17(SNHG17)与p57的表达相关性及功能联系。方法:通过starBase数据库分析SNHG17和p57在肺癌组织和正常组织中的表达差异;采用人正常肺上皮细胞BEAS-2B和人肺癌细胞系A549、H1975进一步分析SNHG17和p57在肺癌细胞和正常肺细胞中的表达差异;采用qRT-PCR和Western印迹检测si-SNHG17在mRNA和蛋白表达方面对SNHG17和p57的影响;采用CCK-8法检测siSNHG17对A549细胞增殖的影响;采用Transwell法检测si-SNHG17对A549细胞迁移和侵袭能力的影响。结果:通过数据分析发现SNHG17在肺腺癌和肺鳞癌组织中显著高表达,而p57在肺腺癌和肺鳞癌组织中却显著低表达;与正常肺细胞相比,SNHG17和p57在肺癌细胞中的表达趋势与在肺癌组织中一致;SNHG17和p57的表达呈负相关;沉默SNHG17使p57的表达一定程度上调,A549细胞的增殖、迁移和侵袭能力受到抑制。结论:SNHG17在肺癌中高表达,促进肺癌细胞增殖,并通过调节p57的表达来抑制肺癌细胞的增殖和迁移。SNHG17和p57在肺癌中的具体作用机制仍有待进一步研究。     

ING5 inhibits cancer aggressiveness by inhibiting Akt and activating p53 in prostate cancer

Prostate cancer (PCa) is one of the most common types of cancer in men. In several recent studies, chromosomal deletions in the q arm of chromosome 2, where ING5 resides within, have been identified in various cancer types including PCa. In this study, we investigate the role of ING5 as a tumor suppressor in PCa. We examined the expression level of ING5 in tissue samples and cell lines using quantitative real‐time polymerase chain reaction and western blot analysis. We tested the in vitro tumor suppressor potential of ING5 in PC3 and LNCaP cells stably overexpressing it using cell viability, colony formation, migration, invasion, and apoptosis assays. We then investigated the effects of ING5 on the Akt and p53 signaling using western blot analysis. We show that ING5 is significantly downregulated in PCa tumor tissue samples and cell lines compared with the corresponding controls. In vitro assays demonstrate that ING5 effectively suppresses proliferative, clonogenic, migratory, and invasive potential and induce apoptosis in PCa cells. ING5 may potentially exert its anti‐tumor potential by inhibiting AKT and inducing p53 signaling pathways. Our findings demonstrate that ING5 possesses tumor suppressor roles in vitro, pointing its importance during the prostatic carcinogenesis processes.     

突变p53功能研究新进展与个性化的肿瘤治疗新策略

p53是迄今为止研究最多的一种抑癌蛋白,最新研究仍在不断地揭示p53在调控机体代谢、生殖方面的新功能。同时,也揭示了不同p53突变蛋白的获得性新功能在肿瘤发生中的促进作用。这些研究对于了解p53突变的个性化新功能,寻找再激活野生型p53,校正突变p53的新途径奠定了基础,不同突变p53蛋白的个性化治疗将是未来肿瘤治疗的热点。文章综述了已发现的一些突变p53的获得性新功能,及针对不同的p53功能缺陷进行的p53蛋白功能再激活的策略:通过小分子或多肽再激活肿瘤细胞中的p53突变蛋白的野生型功能;通过重组的腺病毒在肿瘤细胞中表达野生型p53蛋白;通过抑制MDM2与p53的相互作用稳定野生型p53蛋白。对p53不同位点突变的深入研究可以帮助我们制定更合理的个性化治疗方案,寻求更有效的肿瘤治疗新途径。     

非小细胞肺癌6号染色体长臂的杂合性缺失的微卫星扫描分析

为探讨6号染色体长臂上与非小细胞肺癌发生相关的微卫星位点,应用多重PCR对41例非小细胞肺癌中6号染色体长臂上的36个微卫星位点进行扩增。PCR产物应用聚丙烯酰胶凝胶电泳分离,电泳结果用GeneScan^TM、Genotyper^TM软件进行分析。结果发现各个位点有明显不同的LOH频率,除D6S1579在41例非小细胞肺癌中未发现杂合性缺失外,其余35个位点均有至少一个位点发生突变,LOH频率从3.57%到75%不等,总LOH频率为78%（32/41）,其中D6S302位点的LOH频率最高（75%）。LOH频率超过20%的位点共有14个,主要分布在2个区域。其中有6个位点：D6S458（21.43%)、D6S1694（26.92%）、D6S1717（35.71%）、D6S1565（40%）、D6S302（75%）、D6S1706（36.36%）分布在6q21附近,具体区域是6q16.3-q21;有5个位点：D6S1550（38.4%）、D6S264（20%）、DS1585（25%）、D6S446（33.3%）、D6S281（30.77%）分布在6q27附近,具体区域是6q26-q27。因此6q21、q27附近可能存在与非小细胞肺癌发生相关的巳知或未知肿瘤抑制基因。     

非小细胞肺癌脑部转移瘤适形与调强放疗的剂量研究

为探讨NSCLC脑部转移瘤调强放疗与适形放疗的剂量特点,本研究选取57例非小细胞肺癌脑转移瘤患者,其中单个脑转移灶患者5例,多个脑转移灶患者52例,分别设计全脑放疗+适形放疗与调强放疗计划,用均匀指数(HI)和适形指数(CI)评价靶区剂量,危及器官(OAR)剂量用近似最大剂量D_2%(串联)和中位剂量D_50%(并联)进行评价。研究发现,单个脑转移灶IMRT与WBRT+CRT比较中,CI为(PTV,(0.80±0.15) cGy,(0.34±0.19) cGy, p=0.00),HI为(PTV,(0.52±0.03) c Gy,(0.71±0.12) cGy, p=0.24),两者OARs剂量比较:脑干为((4 348±236) cGy,(4 593±149) cGy, p=0.01),脑垂体为((4 258±166) cGy,(4 581±123) cGy, p=0.02);在多个脑转移灶中,IMRT与WBRT+CRT比,较CI为(PTV,(0.59±0.33) cGy,(0.49±0.27) cGy, p=0.03),HI为(PTV,(0.93±0.01) cGy,(0.58±0.03) cGy, p=0.19),两者OARs剂量比较:脑干为((4 946±132) cGy,(4 843±196) cGy, p=0.51),脑垂体为((4 597±180) cGy,(4 705±149) cGy, p=0.70)。本研究的结果说明,单个脑转移灶患者,IMRT较WBRT+CRT有更好的靶区适形性、稍差的靶区异质性,脑干和垂体的IMRT剂量低于WBRT+CRT,而眼球、晶体的剂量两者差别不明显。多个脑转移灶患者,IMRT较WBRT+CRT有更好的靶区适形性、稍差的靶区异质性,而OARs剂量,IMRT较WBRT+CRT差异不明显。在临床实践过程中,应当根据患者不同的病灶情况选择合适的放疗方案,以获取更优的临床治疗效果。     

细胞周期蛋白依赖激酶Roscovitine诱导非小细胞肺癌A549细胞凋亡及其机制的研究

目的：探讨细胞周期蛋白依赖激酶（CDK）抑制剂Roseovitine（Ros）诱导非小细胞肺癌（NSCLC）A549细胞凋亡及其作用机制。方法：以不同浓度Ros（101．1M、20yM、40μM）处理细胞24h,采用AnnexinV-PI染色以流式细胞仪检测细胞凋亡,Westernblot法检测胞浆中和线粒体促凋亡蛋白Bax和Bad的表达,流式细胞仪检测线粒体膜电位（脚）变化。结果：Ros以剂量依赖的方式诱导A549细胞凋亡,同时Bad和Bax在胞浆的含量随着Ros剂量的增加而减少,而在线粒体中却出现相反的结果,线粒体膜电位随Ros剂量的增大而降低。结论：Ros可通过促进Bax和Bad由胞浆向线粒体易位,诱导NSCLCA549细胞由线粒体途径发生凋亡。     

非小细胞肺癌组织CENPF、KLF4表达与上皮-间质转化和预后的关系研究

摘要 目的：探讨非小细胞肺癌（NSCLC）组织中着丝粒蛋白F（CENPF）、Krüppel样因子4（KLF4）表达与上皮-间质转化（EMT）和预后的关系。方法：选取2017年1月至2019年12月期间于泰州市第四人民医院行手术切除的120例NSCLC患者的癌组织和距癌组织5cm癌旁组织标本,采用免疫组织化学法和免疫印迹法检测癌组织和癌旁组织中CENPF、KLF4及ETM相关标志物[E-钙粘蛋白（E-cadherin）、波形蛋白（Vimentin）]的阳性表达率和表达量。采用Pearson检验分析CENPF、KLF4与EMT相关标志物的相关性,并分析CENPF、KLF4表达与NSCLC患者预后的关系。结果：NSCLC癌组织中CENPF、Vimentin的阳性表达率显著高于癌旁组织（均P<0.05）,而KLF4、E-cadherin的阳性表达率均显著低于癌旁组织（均P<0.05）。NSCLC癌组织中CENPF与E-cadherin呈负相关,与Vimentin呈正相关（P<0.05）;而KLF4与E-cadherin呈正相关,与Vimentin呈负相关（P<0.05）。NSCLC癌组织中CENPF、KLF4的阳性表达率与TNM分期和淋巴结转移有关（均P<0.05）。入组患者3年无病生存率（DFS）为60.00%。CENPF阳性表达的NSCLC患者3年DFS显著低于CENPF阴性表达患者（56.25% vs 75.00%,P=0.014）,KLF4阳性表达的NSCLC患者3年DFS显著高于KLF4阴性表达患者（68.75% vs 54.17%, P=0.048）。结论：CENPF的高表达及KLF4的低表达可促进NSCLC的EMT发生、进展,并导致患者预后不良,CENPF和KLF4可辅助预测NSCLC患者的预后。     

PKCdelta requires p53 for suppression of the transformed phenotype in human colon cancer cells

We have previously demonstrated that the delta isoform of Protein Kinase C (PKCdelta) acts as a tumor suppressor in HCT116 human colon cancer cells, and that p21(waf1/cip1) is an essential downstream effector of PKCdelta. Our data suggested that p53 might also be involved in the suppression of the neoplastic phenotype induced by PKCdelta. Here we show that homozygous knockout of p53 renders the HCT116 cell line unresponsive to PKCdelta overexpression. Whereas reconstitution of p53 alone did not modify the morphology and growth properties of HCT116/p53null cells, overexpression of both p53 and PKCdelta induced a number of alterations indicating suppression of the transformed phenotype. Interestingly, PKCdelta was ineffective when overexpressed in HT29 cells, a human colon cancer line characterized by the Arg273His dominant-negative mutation of p53. Thus, our data indicate that wild-type p53 is an essential effector of PKCdelta in human colon cancer cells.     

细胞周期蛋白依赖激酶Roscovitine 诱导非小细胞肺癌A549 细胞凋亡及 其机制的研究

目的:探讨细胞周期蛋白依赖激酶(CDK)抑制剂Roscovitine(Ros)诱导非小细胞肺癌(NSCLC)A549细胞凋亡及其作用机制。方法:以不同浓度Ros(10μM、20μM、40μM)处理细胞24h,采用Annexin V-PI染色以流式细胞仪检测细胞凋亡,Westernblot法检测胞浆中和线粒体促凋亡蛋白Bax和Bad的表达,流式细胞仪检测线粒体膜电位(MMP)变化。结果:Ros以剂量依赖的方式诱导A549细胞凋亡,同时Bad和Bax在胞浆的含量随着Ros剂量的增加而减少,而在线粒体中却出现相反的结果,线粒体膜电位随Ros剂量的增大而降低。结论:Ros可通过促进Bax和Bad由胞浆向线粒体易位,诱导NSCLC A549细胞由线粒体途径发生凋亡。