前列腺干细胞抗原（PSCA）在肿瘤诊断及治疗中的应用*

前列腺干细胞抗原(PSCA)是最早发现于前列腺癌的GPI锚定的细胞膜蛋白,PSCA的在正常或肿瘤细胞中的具体的病理生理功能还不清楚。PSCA在前列腺癌、胰腺癌、膀胱癌等肿瘤中表达增加,相反在食管癌和胃癌中表达降低可能在胃上皮中发挥肿瘤抑制功能,PSCA发挥致瘤和抑瘤两种截然不同的作用与细胞所处的环境不同有关。除此之外,PSCA作为肿瘤的免疫治疗的靶点也显示出其良好的临床应用潜力。因此PSCA不仅成为肿瘤诊断和预后判断的生物学标记也是肿瘤免疫治疗重要的候选靶蛋白。本文对PSCA的功能和在前列腺癌以及其他肿瘤的临床诊断、预后判断以及治疗应用中的研究进展进行了综述,并讨论了未来PSCA的研究前景。     

MSX1通过与GRP78相互作用促进前列腺癌细胞PC-3增殖

同源异型框蛋白在发育中具有非常重要的作用,而同源异型框蛋白的异常表达和很多人类疾病相关,其中就包括前列腺癌的发生发展。我们通过分析TCGA数据库中前列腺癌病人样本MSX1的表达量发现,在肿瘤样本中MSX1表达量显著高于非肿瘤样本。因此我们检测正常永生化前列腺基底细胞系WPMY-1、雄激素依赖的前列腺癌细胞系LNCa P、雄激素非依赖的前列腺癌细胞系PC-3中MSX1的表达量,发现在雄激素依赖的前列腺癌细胞系LNCa P中MSX1表达量最高。为了探究MSX1在前列腺癌细胞中的作用,我们选取MSX1表达量较低且不受雄激素调控的PC-3细胞作为研究对象。研究表明过表达MSX1可以显著促进PC-3细胞的增殖。我们通过免疫沉淀技术确定了MSX1与GRP78蛋白相互作用,而GRP78蛋白可以调控AKT、ERK1/2等细胞周期相关蛋白从而调控细胞周期等细胞进程。因此推测MSX1通过和GRP78相互作用从而促进前列腺癌细胞增殖。我们的研究为阐明MSX1在前列腺癌发生发展中作用机理提供了一定的理论参考依据。     

Podocin蛋白对肾小球足细胞的影响

目的：探讨肾小球足细胞裂隙膜蛋白podocin对足细胞形态及蛋白尿的影响.方法：32只体重160g～220g的雄性SD大鼠按阿霉素给药剂量随机分成小剂量组（3.0mg/Kg）、肾病剂量组（7.5mg/Kg）、超剂量组（10.0mg/Kg）、正常对照组.于给药第三周末处死大鼠,用氯化苄乙氧铵比浊法检测大鼠24h尿蛋白量,用免疫胶体金电镜检测大鼠肾小球蛋白podocin的表达和足细胞形态.结果：阿霉素组大鼠24h尿蛋白排泄量明显高于正常对照组,尤以肾病组最明显（P＜0.05）;正常对照组大鼠podocin分布在靠近肾小球基底膜（GBM）的足突基底部,主要定位于裂隙隔膜的胞质面,部分金颗粒也可发现于GBM稍远的足突细胞表面.肾病组肾小球足突广泛融合,免疫胶体金颗粒几乎见不到;超剂量组和小剂量组podocin分布在靠近肾小球基底膜（GBM）的足突基底部,免疫胶体金颗粒数明显少于正常对照组,有部分足突退缩.结论：（1）podocin表达减少或消失可能是导致肾小球足突细胞融合的关键因素（2）蛋白尿的发生与肾小球足细胞裂隙膜蛋白podocin的减少或缺失有关.     

中枢神经系统轴突再生抑制蛋白

中枢神经系统 (CNS)轴突再生的主要障碍之一是存在抑制再生的蛋白 ,迄今 ,已在少突胶质细胞 /髓鞘中相继发现至少三个重要的轴突再生抑制蛋白 ,即髓鞘相关糖蛋白 (MAG)、Nogo A和少突胶质细胞 /髓鞘糖蛋白 (OMgp)。最近的研究又证实 ,这三个不同的抑制成分可能主要通过与一个共同的受体Nogo6 6受体 (NgR)结合而发挥作用。这些研究成果扩充了对CNS损伤后轴突再生障碍的理解 ,也为探讨CNS损伤的治疗新策略提供了新的思路。     

多头绒泡菌中动蛋白的免疫化学鉴定

动蛋白(kinesin)是一种微管系统的运动蛋白(motor protein),它能通过水解ATP将化学能转化为机械能,推动微管产生运动.微管系统作为一种主要的细胞骨架存在于所有真核细胞中,它们对于维持细胞形态,细胞的分裂,染色体的运动及细胞内的物质运输起着重要作用.细胞质力蛋白(dynein)和动蛋白是公认的推动这类运动的运动蛋白.自从1985年Vole首次在鱿鱼大轴突(squidgiant axon)中发现动蛋白以来,人们先后在许多种动物细胞中发现有动蛋白存在,甚至在低等真核生物棘状变形虫,盘基网柄茵和高等植物烟草花粉管中发现有动蛋白的存在.研究结果表明,动蛋白参与了真核细胞中的许多重要生命活动,如细胞中的细胞器及囊泡的运动,染色体排裂和分离等运动.动蛋白很可能是普通存在于所有真核细胞中的一种运动蛋白.多头绒泡菌(Physarum poly-cephalum)属于粘菌纲(Myxomycetes)的一种低等真核生物,它表现出许多显著的细胞运动特征如原生质团迁移,细胞质的穿梭运动(shuttle streaming)等,是研究非肌细胞运动和收缩蛋白的经典材料.在多头绒泡菌胞质中也具有微管系统,它们构成其纺锤丝等,参与染色体的运动及其它胞质运动,但至今国内外尚无人证明其中有与微管作用的运动蛋白——动蛋白的存在,作者利用抗牛脑动蛋白的单克隆抗体,     

不同年龄段前列腺外周带基质细胞超微结构差异

目的:研究不同年龄段前列腺外周带基质细胞超微结构并探讨其意义。方法:透射电镜观察3例年轻组(23-、26-、32-岁)和3例老年组(56-、64-、71-岁)正常前列腺外周带和3例前列腺癌组织的超微结构。Masson’s Trichrome染色法观察前列腺外周带基质胶原的分布情况。结果:年轻组、老年组前列腺外周带间质均以平滑肌细胞分布为主,间杂成纤维细胞,但老年组平滑肌细胞和成纤维细胞体积较大、形态不规则。与正常年轻组相比,老年组前列腺外周带成纤维细胞存在明显老化和肌化改变,部分细胞内与蛋白合成相关的细胞器粗面内质网发达,呈现肌成纤维细胞特征。与年轻组和老年组外周带相比,前列腺癌基质中功能更加活跃的肌成纤维细胞和胶原蛋白数量增加明显。Masson’s Trichrome染色支持超微观察到的基质胶原分布差异:年轻组<老年组<前列腺癌组。结论:不同年龄段前列腺外周带基质细胞超微结构间存在差异,老年组前列腺外周带和前列腺癌基质组织中具有活性的肌成纤维细胞的增加可能是造成老年前列腺癌高发和恶性进展的重要病理基础之一。     

四丁基丙二胺对人前列腺癌PC-3细胞生长、凋亡及迁移能力的影响

多胺类似物干扰正常多胺代谢,耗竭肿瘤快速生长必须的多胺。综合(3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide,MTT)法、流式细胞术、琼脂糖凝胶电泳、细胞划痕和Transwell技术以及Western-blot分析四丁基丙二胺对肿瘤细胞生长、凋亡及侵袭能力的影响。研究发现,四丁基丙二胺可明显抑制人前列腺癌PC-3细胞的生长,抑制效应呈浓度和时间的依赖性。四丁基丙二胺可诱导人前列腺癌PC-3细胞染色体DNA发生片段化降解,降低细胞内凋亡抑制蛋白(B cell lymphoma/lewkmia-2,Bcl-2)水平,但增加促凋亡蛋白细胞色素C在胞浆中的含量,明显抑制细胞周期并降低细胞的转移能力。结果表明四丁基丙二胺可抑制人前列腺癌PC-3细胞增殖和迁移,其机制与干扰细胞周期和诱导细胞凋亡密切相关。     

两个新的前列腺癌相关分泌蛋白的鉴定和表达

为了获得代表不同前列腺癌进展阶段的细胞系的胞外蛋白表达谱, 验证其中差异表达蛋白是否为分泌蛋白, 在细胞水平看其是否有作为前列腺癌血清标志物的潜质, 文章利用双向电泳寻找胞外蛋白中差异表达的点, 并质谱鉴定其是何种蛋白质。应用RT-PCR方法分析候选分子在8种细胞系中的表达和对雄激素刺激的应答, 构建了候选分子的真核表达载体, 瞬时转染293T细胞, 应用标签抗体Western blotting方法检测验证细胞培养基中候选分子的表达。结果表明: 筛选出两个C4-2胞外高表达的分子-- 磷酸丙糖异构酶-1(Triosephosphate isomerase 1, TPI1)和多配体聚糖结合蛋白(Syndecan binding protein, syntenin, ST1); 转录水平发现它们与前列腺癌恶性程度相关, 并且后者受雄激素的作用下调; 二者均为分泌蛋白。磷酸丙糖异构酶-1和多配体聚糖结合蛋白均有作为指示前列腺癌发展阶段的血清标志物的潜质。     

PC-1在前列腺癌细胞中促进c-myc基因的表达

前列腺癌相关基因PC-1(Prostate and colon gene1)是属于癌基因D52家族成员,具有促进前列腺癌细胞雄激素非依赖性生长的功能。为了研究PC-1发挥这种生物功能的分子机制,文章在PC-1高表达的LNCaP-pc-1及对照LNCaP-zero细胞中,利用RT-PCR和Western blotting等方法检测c-myc基因表达;提取两细胞胞质和胞核蛋白,利用Western blotting分析c-myc上游调节蛋白β-catenin变化;利用c-Myc蛋白抑制剂10058-F4作用前列腺癌细胞C4-2,Western blotting检测PC-1蛋白表达变化。发现PC-1促进c-myc基因表达,并促进β-catenin入核;c-Myc蛋白抑制剂10058-F4可抑制PC-1的表达。结果表明:PC-1在前列腺癌中促进c-myc基因的表达,并且这种促进作用可能是通过Wnt/β-catenin信号通路实现的。同时,PC-1与c-Myc蛋白间可相互促进,进一步促进前列腺癌细胞雄激素非依赖性生长。     

脑缺血后HSP70表达的研究进展

Ritosso ( 1 962 )首先发现环境温度高于正常生理温度 4℃～ 6℃时 ,染色体上会出现特殊的膨突( Puffs) ,称其为热休克现象。后来 Tissieres等发现染色体的这一膨突与细胞中的一类特殊蛋白质的合成有关 ,并将这一类特殊蛋白质称为热休克蛋白 ( Heatshock protein,HSP)或热应激蛋白。近年来研究发现缺血性细胞损伤可以出现 HSP的表达 [1] ,还发现 HSP对受损细胞有保护作用。1　 HSP的分类　　 70 k Da家族是 HSP中最保守和最主要的一类 ,包括 68、70、72及 78k Da的 HSP。其中 HSP70是在缺血性脑损伤中研究最广泛的一种。氨基酸顺…     

Nuclear dreams: The malignant alteration of nuclear architecture

Cancer is diagnosed by examining the architectural alterations to cells and tissues. Changes in nuclear structure are among the most universal of these and include increases in nuclear size, deformities in nuclear shape, and changes in the internal organization of the nucleus. These may all reflect changes in the nuclear matrix, a non-chromatin nuclear scaffolding determining nuclear form, higher order chromatin folding, and the spatial organization of nucleic acid metabolism. Malignancy-induced changes in this structure may have profound effects on chromatin folding, on the fidelity of genome replication, and on gene expression. Elucidating the mechanisms and the biological consequences of nuclear changes will require the identification of the major structural molecules of the internal nuclear matrix and an understanding of their assembly into structural elements. If biochemical correlates to malignant alterations in nuclear structure can be identified then nuclear matrix proteins and, perhaps nuclear matrix-associated structural RNAs, may be an attractive set of diagnostic markers and therapeutic targets. J. Cell. Biochem. 70:172–180, 1998. © 1998 Wiley-Liss, Inc.     

Concentration-dependent Effects of Nuclear Lamins on Nuclear Size in Xenopus and Mammalian Cells

A fundamental question in cell biology concerns the regulation of organelle size. While nuclear size is exquisitely controlled in different cell types, inappropriate nuclear enlargement is used to diagnose and stage cancer. Clarifying the functional significance of nuclear size necessitates an understanding of the mechanisms and proteins that control nuclear size. One structural component implicated in the regulation of nuclear morphology is the nuclear lamina, a meshwork of intermediate lamin filaments that lines the inner nuclear membrane. However, there has not been a systematic investigation of how the level and type of lamin expression influences nuclear size, in part due to difficulties in precisely controlling lamin expression levels in vivo. In this study, we circumvent this limitation by studying nuclei in Xenopus laevis egg and embryo extracts, open biochemical systems that allow for precise manipulation of lamin levels by the addition of recombinant proteins. We find that nuclear growth and size are sensitive to the levels of nuclear lamins, with low and high concentrations increasing and decreasing nuclear size, respectively. Interestingly, each type of lamin that we tested (lamins B1, B2, B3, and A) similarly affected nuclear size whether added alone or in combination, suggesting that total lamin concentration, and not lamin type, is more critical to determining nuclear size. Furthermore, we show that altering lamin levels in vivo, both in Xenopus embryos and mammalian tissue culture cells, also impacts nuclear size. These results have implications for normal development and carcinogenesis where both nuclear size and lamin expression levels change.     

Nuclear microenvironment in cancer diagnosis and treatment

The nuclear architecture plays an important role in the temporal and spatial control of complex functional processes within the nucleus. Alterations in nuclear structures are characteristic of cancer cells and the mechanisms underlying these perturbations may directly contribute to tumor development and progression. In this review, we will highlight aspects of the nuclear microenvironment that are perturbed during tumorigenesis and discuss how a greater understanding of the role of nuclear structure in the control of gene expression can provide new options for cancer diagnosis and treatment.     

Characterization of the nuclear matrix proteins in a transgenic mouse model for prostate cancer

The nuclear matrix (NM) contains a number of proteins that have been found to be associated with transformation. We have previously identified changes in the NM associated with prostate cancer. In this study, we examine the molecular changes that are associated with prostate cancer development in transgenic adenocarcinoma of mouse prostate (TRAMP) model by studying the differences in the NM proteins (NMPs). We collected prostates from the TRAMP males at six critical time points: 6 weeks (puberty), 11 and 19 weeks (development of mild hyperplasia), 25 weeks (development of severe hyperplasia), 31 and 37 weeks (development of neoplasia). The nuclear matrices from the prostates collected at these time points were then isolated and the NMPs were characterized by high-resolution two-dimensional gel electrophoresis. We found three NMPs (E1A, E1B, and E1C) that were present in the 6-week-old prostate and two NMPs (E2A and E2B) that were present in the 11-week-old prostate. These NMPs were absent in the 31- and 37-week-old prostate. We also found five NMPs (E3A-E3E) that were present in the 31-week-old prostate, but absent in the earlier time points. In addition, three NMPs (Le1, Le2, Le3) were present at higher expression in the 6-, 11-, 19-, and 25-weeks old TRAMP prostates, but they were expressed lower during the development of neoplasia at 31- and 37-weeks old. Identification of these NMPs permits the development of novel markers that can characterize various stages of prostate cancer development as well as potentially therapeutic targets.     

Advances in the computational and molecular understanding of the prostate cancer cell nucleus

Nuclear alterations are a hallmark of many types of cancers, including prostate cancer (PCa). Recent evidence shows that subvisual changes, ones that may not be visually perceptible to a pathologist, to the nucleus and its ultrastructural components can precede visual histopathological recognition of cancer. Alterations to nuclear features, such as nuclear size and shape, texture, and spatial architecture, reflect the complex molecular‐level changes that occur during oncogenesis. Quantitative nuclear morphometry, a field that uses computational approaches to identify and quantify malignancy‐induced nuclear changes, can enable a detailed and objective analysis of the PCa cell nucleus. Recent advances in machine learning–based approaches can now automatically mine data related to these changes to aid in the diagnosis, decision making, and prediction of PCa prognoses. In this review, we use PCa as a case study to connect the molecular‐level mechanisms that underlie these nuclear changes to the machine learning computational approaches, bridging the gap between the clinical and computational understanding of PCa. First, we will discuss recent developments to our understanding of the molecular events that drive nuclear alterations in the context of PCa: the role of the nuclear matrix and lamina in size and shape changes, the role of 3‐dimensional chromatin organization and epigenetic modifications in textural changes, and the role of the tumor microenvironment in altering nuclear spatial topology. We will then discuss the advances in the applications of machine learning algorithms to automatically segment nuclei in prostate histopathological images, extract nuclear features to aid in diagnostic decision making, and predict potential outcomes, such as biochemical recurrence and survival. Finally, we will discuss the challenges and opportunities associated with translation of the quantitative nuclear morphometry methodology into the clinical space. Ultimately, accurate identification and quantification of nuclear alterations can contribute to the field of nucleomics and has applications for computationally driven precision oncologic patient care.     

Pleomorphism of the nuclear envelope in breast cancer: a new approach to an old problem

In routine practice, nuclear pleomorphism of tumours is assessed by haematoxylin staining of the membrane-bound heterochromatin. However, decoration of the nuclear envelope (NE) through the immunofluorescence staining of NE proteins such as lamin B and emerin can provide a more objective appreciation of the nuclear shape. In breast cancer, nuclear pleomorphism is one of the least reproducible parameters to score histological grade, thus we sought to use NE proteins to improve the reproducibility of nuclear grading. First, immuno-fluorescence staining of NE as well as confocal microscopy and three-dimensional reconstruction of nuclei in cultured cells showed a smooth and uniform NE of normal breast epithelium in contrast to an irregular foldings of the membrane and the presence of deep invaginations leading to the formation of an intranuclear scaffold of NE-bound tubules in breast cancer cells. Following the above methods and criteria, we recorded the degree of NE pleomorphism (NEP) in a series of 273 invasive breast cancers tested by immunofluorescence. A uniform nuclear shape with few irregularities (low NEP) was observed in 135 cases or, alternatively, marked folds of the NE and an intranuclear tubular scaffold (high NEP cases) were observed in 138 cases. The latter features were significantly correlated (P-value <0.002) with lymph node metastases in 54 histological grade 1 and in 173 cancers with low mitotic count. Decoration of the NE might thus be regarded as a novel diagnostic parameter to define the grade of malignancy, which parallels and enhances that provided by routine histological procedures.     

The use of a colon cancer associated nuclear antigen CCSA-2 for the blood based detection of colon cancer

The early diagnosis of colorectal cancer (CRC) is central for effective treatment, as prognosis is directly related to the stage of the disease. Development of tumor markers found in the blood from patients, which can detect CRC at an early stage, should have a major impact in morbidity and mortality of this disease. The nuclear matrix is the structural scaffolding of the nucleus and specific nuclear matrix proteins (NMPs) have been identified as an "fingerprint" for various cancer types. Previous studies from our laboratory have identified four colon cancer associated NMPs termed colon cancer-specific antigen (CCSA)-2 to (CCSA)-5. The objective of the present study was to analyze the expression of one of these proteins, CCSA-2 in serum from various patient populations and to determine whether CCSA-2 antibodies could be used in a clinically applicable serum-based immunoassay specifically to detect colon cancer. Using an indirect ELISA, which detects CCSA-2, the protein was measured in the serum from 174 individuals, including healthy individuals, patients with colon cancer, patients with diverticulosis, colon polyps, inflammatory bowel disease (IBD) as well as other cancer types. With a predetermined cutoff absorbance of 0.6 OD we have successfully utilized this approach to develop an immunoassay that detected colon cancer. The immunoassay showed a sensitivity of 88.8% (24/27) and an overall specificity of 84.2% (106/127). This initial study showed the potential of CCSA-2 to serve as a highly specific blood based marker for colon cancer. Although potentially promising, the results of this study must be confirmed in larger independent validation studies.     

The importin-alpha/nucleophosmin switch controls taspase1 protease function

Taspase1 is a threonine protease suspected to process (patho)biologically relevant nuclear and cytoplasmic substrates, such as the mixed lineage leukemia protein. However, neither the mechanisms regulating Taspase1's intracellular localization nor their functional consequences are known. Analysis of endogenous and ectopically expressed Taspase1 detected the protease predominantly in the nucleus accumulating at the nucleolus. Microinjection and ectopic expression studies identified an evolutionarily conserved bipartite nuclear import signal (NLS) (amino acids (197) KRNKRKLELA ERVDTDFMQLKKRR(220) ) interacting with importin-α. Notably, an NLS-mutated, import-deficient Taspase1 was biologically inactive. Although the NLS conferred nuclear transport already of the proenzyme, Taspase1's nucleolar localization required its autoproteolytic processing, triggering its interaction with the nucleolar shuttle protein nucleophosmin. In contrast, (auto)catalytically inactive Taspase1 mutants neither accumulated at the nucleolus nor bound nucleophosmin. Active nuclear import and interaction with nucleophosmin was found to be required for the formation of proteolytically active Taspase1 ensuring to efficiently process its nuclear targets. Intriguingly, coexpression of pathological nucleophosmin variants increased the amount of cytoplasmic Taspase1. Hence, Taspase1 appears to exploit the nuclear export activity of nucleophosmin to gain transient access to the cytoplasm required to also cleave its cytoplasmic substrates. Collectively, we here describe a hitherto unknown mechanism regulating the biological activity of this protease.