胃粘膜非典型增生中微环境蛋白质的相互作用北大核心CSCD

微环境在胃癌发病过程中发挥重要作用。了解胃粘膜早期癌变的分子机制,对防治胃癌具有十分重要的意义。为了解胃粘膜非典型增生过程中,微环境中蛋白质的相互作用及调节机制,采用激光捕获显微切割(laser capture microdissection,LCM)技术,纯化正常胃粘膜组织(normal gastric mucosa tissue,NGM)和胃粘膜非典型增生(gastric mucosal atypical hyperplasia,GMAH)间质,通过同位素标记定量蛋白质组学技术分析,鉴定NGM和GMAH间质的差异表达蛋白质。利用生物信息学软件,分析NGM和GMAH间质差异表达蛋白质的相互作用及其联系。共鉴定出165个GMAH间质差异表达蛋白质,其中GMAH组织中表达上调者99个,下调者66个。它们涉及一些与肿瘤相关的信号通路,如p53信号通路、MAPK信号通路、细胞周期与凋亡等信号通路,且与细胞生长、增殖、凋亡和体液免疫应答等生物学过程有关。这些差异表达蛋白质,在STRING网络中呈现相互作用,两两间相互联系。本文的研究提示,胃粘膜非典型增生微环境中存在S100A6和SOD3等蛋白质间的相互作用,它们通过影响p53信号通路、MAPK信号通路、细胞周期与凋亡等信号通路,在胃癌发病过程中发挥作用。     

Hsa-miR-125b在人胃癌耐药细胞株中的表达及其靶基因的功能分析

研究表明, Hsa-miR-125b在人胃癌耐氟尿嘧啶细胞株BGC823/Fu中表达下降。为进一步探讨hsa-miR-125b在获得性耐药中所起的作用, 文章应用miRbase、靶基因预测软件、Gene Ontology数据库及KEGG数据库对hsa-miR-125b的序列特征、进化保守性、靶基因及功能以及靶基因所参与的信号通路等进行了深入的生物信息学分析。结果显示：has-miR-125b在多个物种之间具有高度序列保守性; 通过软件预测获得hsa-miR- 125b 靶基因79个, 其分子功能包括转录调节、蛋白质结合和肽酶类活性等(P<0.001), 其所参与的生物学过程主要有细胞周期、细胞增殖、细胞凋亡的正性或负性调控以及细胞因子刺激反应性、药物反应性、DNA损伤反应性等(P<0.001), 调控包括MAPK、Wnt、p53等多条信号转导通路(P<0.01)。上述结果表明hsa-miR-125b可能参与调控多个生物学过程和信号转导通路, 而其中细胞增殖、细胞凋亡、细胞周期等生物学过程以及MAPK、Wnt、p53等信号通路已被证实与肿瘤耐药的发生有关。因此, hsa-miR-125b可能通过调控上述环节中的靶基因来影响肿瘤细胞对药物的敏感性, 从而为hsa-miR-125b在肿瘤耐药中的作用机制提供新的研究线索。     

肝癌细胞HepG2中p53调控miRNA-3661的生物信息分析与功能验证

对已在前期实验中通过Dox诱导肝癌细胞HepG2 DNA损伤发现的受p53调控的hsa-miR-3661进行生物信息学分析,并通过分子生物学实验对其功能进行了验证,为miR-3661在肝肿瘤中的调控机制的研究提供理论基础。获取miR-3661结构与序列信息;预测靶基因,使用DAVID进行miRNA靶基因功能富集分析;分析miR-3661的p53结合位点,通过基因间的相互作用构建调控网络;进行细胞增殖实验验证miR-3661抑制肿瘤功能。结果表明,miR-3661序列保守,启动子区存在p53结合位点,暗示p53与hsa-miR-3661存在直接调控;预测靶基因1 009个,369个显著富集于细胞周期调控、细胞增殖、细胞凋亡等肿瘤相关生物学过程(P0.05),主要参与了癌症信号通路、MAPK信号通路与Erb B信号通路(P0.05);通过268组基因间的相互作用数据构建了p53、hsa-miR-3661和靶基因的调控网络,从系统生物学角度分析了参与多个肿瘤生物进程的关键靶基因;在实验中证实过表达miR-3661可以显著抑制肝癌细胞HepG2的增殖过程(P-value=0.001 46)。miR-3661受p53直接调控,其靶基因显著富集于多种肿瘤相关生物进程与信号通路,过表达miR-3661可显著抑制肝癌细胞增殖。     

肿瘤细胞中存活蛋白与p53的相互作用

存活蛋白(survivin)作为凋亡抑制蛋白(IAP)家族的最小成员,在肿瘤组织中高表达,且具有严格的细胞周期依赖性,而p53作为细胞周期中的负调节因子,参与了细胞周期调控和细胞凋亡等重要的生物学功能。最近研究表明,存活蛋白与p53的相互作用在肿瘤的发生发展中具有重要作用。该文将从细胞周期与细胞凋亡的角度对存活蛋白/p53通路在肿瘤中的研究进展进行阐明。     

癌相关通路在肺腺癌中的共扰动机制

肺腺癌的发生涉及多个生物学功能通路的扰动,其遗传改变频繁地发生于MAPK信号、p53信号、Wnt信号、细胞周期和mTOR等通路的基因中。解析癌相关通路间的共扰动机制对我们理解癌机制以及寻找诊断标记具有重要意义。因此,本文基于肺腺癌突变谱数据,研究上述癌相关通路在肺腺癌中的共扰动机制。结果发现:在肺腺癌发生的过程中,MAPK信号、p53信号、Wnt信号、细胞周期和mTOR等通路同时被扰动。在不同的癌样本中,一对通路可能通过以下三种方式被共同扰动:(1)在两条通路中的不同基因间的共突变;(2)两条通路相互交叠基因的突变;(3)与两条通路同时具有频繁的互作关系的蛋白质的编码基因的突变。该结果提示,癌相关通路对在不同的样本中可能通过不同的方式被共扰动,这也可能是造成癌症异质性的重要原因之一。     

ERK1/2在食管鳞状细胞癌中促进细胞增殖、抑制凋亡及其调控机制的研究

探讨ERK1/2在食管鳞状细胞癌(ESCC)中对肿瘤细胞增殖、凋亡的调控及其机制。平板克隆、细胞凋亡和细胞周期实验结果发现ERK1/2 MAPK通路抑制可减弱Eca109细胞克隆形成和增殖,促进细胞凋亡,减慢细胞周期;进一步发现ERK1/2 MAPK通路抑制可以反转由mi R-21过表达诱导的Eca109细胞增殖、凋亡和周期的变化;q RT-PCR和Western-blot免疫印迹结果发现ERK1/2 MAPK信号通路抑制可以下调内源性mi R-21表达和反转外源性mi R-21诱导的ERK1/2 MAPK信号通路活化。实验结果提示ERK1/2 MAPK通路抑制可能通过下调Eca109细胞中mi R-21表达阻碍Eca109细胞增殖、促进细胞凋亡和减慢细胞周期,最终导致ESCC细胞生长抑制。     

microRNAs与TP53基因调控网络研究进展

TP53基因(编码p53蛋白)作为一个重要的抑瘤基因,通过调控一系列信号转导通路广泛参与了多种恶性肿瘤的发生发展,一直是肿瘤分子生物学研究领域的热点.最近的研究发现,microRNAs(miRNAs)参与了TP53的信号通路,它们之间存在着复杂的调控网络.一方面,p53通过调控一些miRNAs的转录及转录后成熟,促进细胞周期阻滞、诱导细胞凋亡和衰老,抑制肿瘤发生.另一方面,许多miRNAs,如miR-25、miR-30d、miR-125b和miR-504等可直接调控p53的表达与活性,参与TP53信号通路的调节,还有一些miRNAs则通过调节p53上下游基因,发挥重要的生物学功能.其中,最具有代表性的是miR-34家族,它们受p53直接调控并参与TP53信号通路,通过靶向抑制多个TP53信号通路关键分子的表达,发挥抑瘤作用.此外,它们还可以通过抑制沉默信息调节子,增强p53的活性,反馈调节TP53信号通路.miRNAs与TP53之间调控网络的研究,是对TP53抑瘤机制的重要补充.     

阿霉素诱导下的肝癌细胞HepG2中微小RNA差异表达分析

旨在研究阿霉素诱导引起的DNA损伤压力下,肝癌细胞Hep G2中参与DNA损伤应答的mi RNA,并分析这些mi RNA靶基因参与肝癌DNA损伤应答相关的生物学进程与通路。通过小RNA测序检测阿霉素处理肝癌细胞Hep G2前后mi RNA的差异表达情况,使用GO与KEGG通路富集方法对差异表达mi RNA靶基因进行功能富集分析。结果显示,共检测出显著表达差异mi RNA 68个,其中上调13个,下调55个。mi RNA靶基因的功能分析结果显示,53条mi RNAs靶基因显著富集于调控细胞增殖、细胞凋亡、细胞迁移和细胞周期等与DNA损伤应答以及肿瘤相关的生物进程和信号通路,包括p53信号通路、癌症通路、Wnt信号通路和MAPK信号通路等。研究表明,在阿霉素诱导下,Hep G2中的差异表达mi RNAs与DNA损伤相关的肿瘤生物学进程以及信号通路显著相关,预示这些mi RNAs在阿霉素引发的肝细胞癌DNA损伤应答中起着重要的作用。     

P38MAPK信号通路与心血管疾病关系的研究进展

P38MAPK信号通路是细胞内主要的信息传递途径之一,与其他信号通路相互联系,共同调节细胞增殖、分化、凋亡、细胞骨架重构及细胞周期,在多种心血管疾病发生发展和转归中均起着重要作用。通过阻断和调控P38MAPK的表达和活性,探索防治心血管疾病的新的治疗手段具有重大临床意义。本文拟将P38MAPK与心血管疾病的关系的研究进展做一综述。     

促分裂原激活的蛋白激酶(MAPK)信号传导通路的研究进展

MAPK信号传导通路在真核生物细胞的生化和分化、细胞周期调节和细胞凋亡过程中发挥着重要的作用。生物化学研究和分子生物学鉴定表明：在酵母和哺乳动物细胞中MAPK信号传导通路都有一个保守的三组分激活模件,该模件内的激酶引发了一系列的磷酸化级联反应。了解MAPK信号传导通路的组成部分、调控方式和作用机制,有助于对因信号传导通路的调节失控而引起的疾病进行预防和治疗。     

Physiological roles of mitogen-activated-protein-kinase-activated p38-regulated/activated protein kinase

Mitogen-activated protein kinases (MAPKs) are a family of proteins that constitute signaling pathways involved in processes that control gene expression, cell division, cell survival, apoptosis, metabolism, differentiation and motility. The MAPK pathways can be divided into conventional and atypical MAPK pathways. The first group converts a signal into a cellular response through a relay of three consecutive phosphorylation events exerted by MAPK kinase kinases, MAPK kinase, and MAPK. Atypical MAPK pathways are not organized into this three-tiered cascade. MAPK that belongs to both conventional and atypical MAPK pathways can phosphorylate both non-protein kinase substrates and other protein kinases. The latter are referred to as MAPK-activated protein kinases. This review focuses on one such MAPK-activated protein kinase, MAPK-activated protein kinase 5 (MK5) or p38-regulated/activated protein kinase (PRAK). This protein is highly conserved throughout the animal kingdom and seems to be the target of both conventional and atypical MAPK pathways. Recent findings on the regulation of the activity and subcellular localization, bona fide interaction partners and physiological roles of MK5/PRAK are discussed.     

The involvement of MAPK signaling pathways in determining the cellular response to p53 activation: cell cycle arrest or apoptosis

The effect of ERK, p38, and JNK signaling on p53-dependent apoptosis and cell cycle arrest was investigated using a Friend murine erythroleukemia virus (FVP)-transformed cell line that expresses a temperature-sensitive p53 allele, DP16.1/p53ts. In response to p53 activation at 32 degrees C, DP16.1/p53ts cells undergo p53-dependent G(1) cell cycle arrest and apoptosis. As a result of viral transformation, these cells express the spleen focus forming env-related glycoprotein gp55, which can bind to the erythropoietin receptor (EPO-R) and mimics many aspects of EPO-induced EPO-R signaling. We demonstrate that ERK, p38 and JNK mitogen-activated protein kinases (MAPKs) are constitutively active in DP16.1/p53ts cells. Constitutive MEK activity contributes to p53-dependent apoptosis and phosphorylation of p53 on serine residue 15. The pro-apoptotic effect of this MAPK kinase signal likely reflects an aberrant Ras proliferative signal arising from FVP-induced viral transformation. Inhibition of MEK alters the p53-dependent cellular response of DP16.1/p53ts from apoptosis to G(1) cell cycle arrest, with a concomitant increase in p21(WAF1), suggesting that the Ras/MEK pathway may influence the cellular response to p53 activation. p38 and JNK activity in DP16.1/p53ts cells is anti-apoptotic and capable of limiting p53-dependent apoptosis at 32 degrees C. Moreover, JNK facilitates p53 protein turnover, which could account for the enhanced apoptotic effects of inhibiting this MAPK pathway in DP16.1/p53ts cells. Overall, these data show that intrinsic MAPK signaling pathways, active in transformed cells, can both positively and negatively influence p53-dependent apoptosis, and illustrate their potential to affect cancer therapies aimed at reconstituting or activating p53 function.     

Scaffold proteins in mammalian MAP kinase cascades

The mitogen-activated protein kinase (MAPK) signaling pathway, which is conserved from yeast to humans, is activated in response to a variety of extra- and intracellular stimuli, and plays key roles in multiple cellular processes, including proliferation, differentiation, and apoptosis. The MAPK pathway transmits its signal through the sequential phosphorylation of MAPK kinase kinase to MAPK kinase to MAPK. Specific and efficient activation of the MAPK cascades is crucial for proper cellular responses to stimuli. As shown in yeast, the mammalian MAPK signaling system may also employ scaffold proteins, in part, to organize the MAPK signaling components into functional MAPK modules, thereby enabling the efficient activation of specific MAPK pathways. This review article describes recent advances in the study of potential mammalian scaffold proteins that may help us understand the complex regulation, including the spatial and temporal control, of the mammalian MAPK signaling pathways.     

蛋白质组学技术对不同性别中国美利奴细毛羊(军垦型) 皮肤差异蛋白的筛选

旨在了解性别因素对绵羊毛性状的影响。以周岁雄性和雌性中国美利奴羊（军垦型）为研究对象,利用液相色谱-串联质谱联用技术和数据非依赖性采集策略的定量蛋白质组学技术筛选皮肤组织差异表达蛋白,并对筛选获得的差异蛋白进行基因本体（gene ontology,GO）功能注释、京都基因与基因组百科全书（Kyoto encyclopedia of genes and genomes,KEGG）代谢通路和蛋白互作分析。结果显示,共计筛选获得差异表达蛋白674种,其中,280种蛋白表达上调,394种蛋白表达下调;通过进一步分析发现,与皮肤毛囊发育及羊毛表型相关的差异蛋白有43种,上调差异蛋白30种,下调差异蛋白13种。GO注释结果显示,在分子功能方面,差异蛋白在氧结合、硫酸软骨素结合、亚铁血红素结合、谷胱甘肽过氧化物酶活性和转运活性等37个过程显著富集;在生物过程方面,差异蛋白在细胞氧化解毒作用、肌肉收缩调节、Notch信号通路、钙离子跨膜转运和谷胱甘肽新陈代谢等120个过程显著富集;在细胞组分方面,主要富集在肥大细胞颗粒、细胞核、肌质网状组织和内质网等31个过程。KEGG通路结果表明,这些差异蛋白涉及16条信号通路,其中,MAPK、P53信号通路和羊毛生长发育密切相关。蛋白质网络互作结果显示,COL1A1蛋白与MMP2、SPARC、THBS1等差异表达蛋白联系较为紧密,其可能在羊毛生长发育过程中发挥着关键作用。本研究为揭示不同性别绵羊毛性状的分子机制积累了基础数据。     

Anti-tumor activity of the X-linked inhibitor of apoptosis (XIAP) inhibitor embelin in gastric cancer cells

This study investigated the anticancer effects of embelin in human gastric cancer cells and the underlying molecular mechanisms. Gastric cancer cells were treated with embelin and 5-FU for methyl-thiazolyl-tetrazolium bromide cell viability assay and flow cytometric detection of cell viability and apoptosis. Protein pathway array (PPA) and Western blot were used to investigate differentially expressed proteins in embelin-treated gastric cancer cells. Embelin reduced gastric cancer cell viability, induced apoptosis, and enhanced 5-FU antitumor activity in gastric cancer cells. Mechanistically, embelin induced cell cycle arrest at the S and G2/M phases. Molecularly, embelin downregulated expression of X-linked inhibitor of apoptosis and cell cycle-regulatory proteins, such as CDK1, CDC25B, CDC25C, cyclinB1, and CDK2. PPA analysis showed that embelin modulated several pathways that are associated with cell growth and apoptosis, such as PI3K/AKT, JAK/STAT, p38 MAPK, and p53. The data from the current study implied that reduction of gastric cancer cell viability after treatment with embelin was through cell cycle arrest at the S and G2/M phases and apoptosis.     

TNF‐α regulates the early development of avascular necrosis of the femoral head by mediating osteoblast autophagy and apoptosis via the p38 MAPK/NF‐κB signaling pathway

Previous studies have shown that the tumor necrosis factor‐α (TNF‐α) levels in serum and bone tissues formed in avascular necrosis of femoral head (ANFH) patients were higher than those of normal individuals, indicating TNF‐α might play a role in the pathogenesis of ANFH. However, the underlying mechanisms remain unclear. Hematoxylin and eosin staining was performed to show the pathological changes of ANFH bone tissues. TNF‐α expression in normal and ANFH tissues was examined by quantitative real‐time polymerase chain reaction and western blot analyses. Osteoblast autophagy and apoptosis, as well as signaling pathways activation, were measured by their corresponding marker proteins. Osteoblast proliferation, autophagy, and apoptosis were evaluated using cell counting kit‐8, transmission electron microscopy, and flow cytometry. The structures of bone tissues of ANFH were obviously damaged. TNF‐α expression was significantly upregulated in ANFH bone tissues compared to normal tissues. Autophagy and apoptosis were remarkably promoted, and p38 mitogen‐activated protein kinase (MAPK)/nuclear factor‐κB (NF‐κB) signaling pathways were markedly activated in ANFH. Suppression of the p38 MAPK/NF‐κB pathway significantly attenuated the TNF‐α‐induced autophagy, however, enhanced the TNF‐α‐induced apoptosis in osteoblasts. Increased TNF‐α in ANFH regulated osteoblast autophagy and apoptosis by p38 MAPK/NF‐κB signaling pathways, blocking the pathway by inhibitors exacerbated TNF‐α‐induced apoptosis through impairing autophagy flux.     

Ganoderma lucidum polysaccharide exerts anti-tumor activity via MAPK pathways in HL-60 acute leukemia cells

In this study, we investigated the anti-tumor activity both in vitro and in vivo of a polysaccharide obtained from Ganoderma lucidum on HL-60 acute myeloid leukemia cells, and focused on its targeting effect on mitogen-activated protein kinase (MAPK) pathways. It was found by the methods such as western blot and flow cytometry (FCM), that G. lucidum polysaccharide (GLP) blocked the extracellular signal-regulated kinase/MAPK signaling pathway, simultaneously activated p38 and JNK MAPK pathways, and therefore regulated their downstream genes and proteins, including p53, c-myc, c-fos, c-jun, Bcl-2, Bax, cleaved caspase-3 and cyclin D1. As a result, cycle arrest and apoptosis of HL-60 cells were induced. Therefore, GLP exerted anti-tumor activity via MAPK pathways in HL-60 acute leukemia cells.