Notch3在肿瘤发生发展中的作用

Notch信号通路是一个高度保守的信号通路,在脊椎动物发育过程中扮演重要角色。研究发现Notch受体介导的信号通路在多种肿瘤中异常表达。近年来研究表明Notch3与多种肿瘤的发生发展有着密切的联系,Notch3在调控肿瘤细胞的凋亡、增殖和分化中起着重要作用,本文就Notch3在各类常见肿瘤中的研究进展进行综述,重点探讨Notch3异常表达与肿瘤形成、发展的分子机制,以期推动Notch3作为药物作用靶点的研究。     

Notch信号通路在肿瘤干细胞中的研究进展

肿瘤干细胞是一类具有自我更新分化能力,在移植动物宿主中具有致瘤性且对放化疗抵抗的细胞小亚群,是肿瘤复发转移的主要原因。Notch信号通路在进化中高度保守,具有调控细胞增殖、分化和凋亡的功能,且在维持肿瘤干细胞的干细胞特性方面发挥重要作用,在干细胞中与多个信号通路存在交互作用。通过抑制Notch信号通路靶向作用肿瘤干细胞的治疗策略已进入临床试验阶段,具有广阔的发展前景。全文就Notch信号通路在肿瘤干细胞中的作用及其与Wnt、TGF-β、Her-2信号通路的交互作用进行阐述与分析。     

Notch信号通路与脑肿瘤

Notch信号通路作为一个对细胞的生长发育具有广泛多样化影响的信号途径,也与肿瘤的发生、发展相关.对于不同的肿瘤或同一肿瘤的不同级别、不同发展阶段Notch信号通路可能具有不同作用.Notch信号在一些脑肿瘤(脑胶质瘤、髓母细胞瘤、神经母细胞瘤、脑膜瘤)中异常表达,且参与这些脑肿瘤的发生、发展.     

髓母细胞瘤干细胞

髓母细胞瘤和其他胚胎性脑肿瘤在形态和分化上同神经干细胞和祖细胞相似。通过人类肿瘤标本的基因表达研究和转基因鼠模型分析．提示多能外胚层小脑干细胞和谱系限制性的祖细胞可以通过基因的改变转化为髓母细胞瘤。这些分子的改变常常涉及到Wnt、Hedgehog和Notch等信号通路的组成性激活．这些信号通路在非肿瘤性神经干细胞中发挥重要作用。通过药物阻断Hedgehog和Notch信号通路在体外培养和体内均可抑制髓母细胞瘤的生长．这个可以证明对于肿瘤的发生和长期增殖所必须的小肿瘤干细胞亚群以上述信号通路为靶点阻滞是有效的。     

Notch信号通路在头颈部肿瘤中的研究进展

Notch家族是一组进化上高度保守的跨膜蛋白,广泛存在于细胞表面,对细胞生物活性起重要作用.Notch信号通路参与调控机体正常细胞的分化、增殖和凋亡.Notch信号通路的异常激活在一定程度上能够促进细胞的过度增殖和恶性转化,有效抑制Notch信号通路的活性可抑制肿瘤细胞的生长和增殖,并能够诱导肿瘤细胞的凋亡,为肿瘤治疗开辟新途径.现有研究证实Notch信号通路的活化和抑制与头颈部肿瘤密切相关.通过对Notch信号通路进行调节,可能为头颈部肿瘤的治疗提供新的靶点.本文对Notch信号通路的结构特点、功能及其在头颈部肿瘤中的研究进展进行综述.     

Notch信号通路在乳腺癌干细胞中的研究进展

乳腺癌干细胞是一群具有自我更新及多向分化潜能的细胞,在乳腺癌的发生、发展以及转移、复发中起着极其重要的作用。正常情况下,乳腺干细胞的分化、更新能力受相关信号转导通路的严格调控,当这些信号通路发生异常干细胞将会异常分化,形成乳腺癌干细胞,并无限增殖形成肿瘤。随着人们对乳腺癌干细胞的深入研究,Notch信号通路与其他信号通路的相互作用对乳腺癌干细胞的调控逐渐被人们所重视。本文为进一步了解Notch信号通路在乳腺癌的发生、发展以及靶向治疗中的重要意义,结合乳腺癌干细胞信号通路的最新研究进展进行综述。      

Notch3信号通路与卵巢癌发生发展关系的研究北大核心CSCD

Notch信号传导通路是影响细胞命运的重要通路之一,相邻细胞间通过Notch受体传递信号可以调节多种细胞的分化、增殖和凋亡,影响器官形成和形态变化。Notch信号传导的变化与肿瘤的发生发展密切相关,如脑肿瘤、乳腺癌、肝癌等。近年来研究表明,Notch异常通路介导卵巢癌的发生发展,尤其Notch3及其信号传导分子参与肿瘤的化疗耐药与复发。文章对新近有关Notch3信号通路的重要分子调控卵巢癌的发生发展进行综述。     

Notch信号转导通路与原发性肝癌

Notch信号转导通路由一组在进化上高度保守的细胞膜配体、受体及下游分子组成。细胞间受体配体作用可激活Notch信号转导过程,从而直接调节基因转录,使细胞基因表达受相邻细胞调控,Notch信号在细胞分化、胚胎发育、组织自我更新过程中均发挥了重要的作用,许多病理过程（包括肿瘤）都有Notch信号参与。Notch信号多作为癌基因促进肿瘤生长,但在某些组织也可起到诱导细胞分化、抑制肿瘤增殖的作用。肿瘤干细胞中Notch信号的改变可能发挥了关键性作用。目前认为,Notch在肝癌中作为抑癌基因抑制肿瘤的生长,其机制初步被认为是Notch1使JNK活化、p53高表达以及Bcl2表达下调,从而诱导肝癌细胞凋亡,但尚待更加深入的研究。鉴于针对Notch信号通路的干预措施已经成为治疗肿瘤的新方式,该通路也有望成为肝癌的生物治疗新的靶点。     

Notch信号通路在B细胞分化发育以及B细胞淋巴瘤中作用的研究进展

Notch信号通路是一种在进化中较为保守的信号通路,在多种生命活动中发挥重要作用.目前研究认为,Notch信号参与了免疫细胞的生长、分化和发育等多个环节的调控,其在B细胞的分化发育过程以及相关肿瘤的发生发展中起到重要的调控作用.本文对Notch信号在B细胞的不同分化发育阶段如淋巴祖细胞(common lymphoid progenitor,CLP)、边缘区B细胞(marginal zone B cell,MZ B)、滤泡B细胞(follicular B cell,FO B)、B-1 B细胞,以及B细胞淋巴瘤中的作用进行了综述.     

Notch信号通路对胶质瘤干细胞 作用机制的研究进展

胶质母细胞瘤（GBM）是成人最常见的原发性颅内恶性肿瘤,由于其呈浸润性生长、手术无法彻底切除以及放化疗抵抗等因素,导致临床病情进展快、预后差。近年来多项临床研究表明GBM的侵袭性、高复发性与胶质瘤干细胞（GSCs）存在关联。Notch信号通路参与维持GSCs的特性,调控GSCs的增殖、分化和凋亡。抑制Notch信号通路靶向作用GSCs的临床治疗具有广阔前景。本文综述了GSCs的生物学特征以及Notch信号通路对GSCs的调控机制,拟为GBM的诊断、治疗和科学研究提供新的方向。     

Notch3 activation promotes invasive glioma formation in a tissue site-specific manner

Although Notch signaling has been widely implicated in neoplastic growth, direct evidence for in vivo initiation of neoplasia by the pathway in murine models has been limited to tumors of lymphoid, breast, and choroid plexus cells. To examine tumorigenic potential in the eye and brain, we injected retroviruses encoding activated forms of Notch1, Notch2, or Notch3 into embryonic mice. Interestingly, the majority of animals infected with active Notch3 developed proliferative lesions comprised of pigmented ocular choroid cells, retinal and optic nerve glia, and lens epithelium. Notch3-induced lesions in the choroid, retina, and optic nerve were capable of invading adjacent tissues, suggesting that they were malignant tumors. Although Notch3 activation induced choroidal tumors in up to 67% of eyes, Notch1 or Notch2 activation never resulted in such tumors. Active forms of Notch1 and Notch2 did generate a few small proliferative glial nodules in the retina and optic nerve, whereas Notch3 was 10-fold more efficient at generating growths, many of which were large invasive gliomas. Expression of active Notch1/Notch3 chimeric receptors implicated the RBPjk-association molecule and transactivation domains of Notch3 in generating choroidal and glial tumors, respectively. In contrast to our findings in the optic nerve and retina, introduction of active Notch receptors, including Notch3, into the brain never caused glial tumors. Our results highlight the differential ability of Notch receptor paralogs to initiate malignant tumor formation, and suggest that glial precursors of the optic nerve, but not the brain, are susceptible to transformation by Notch3.     

Critical role of notch signaling in osteosarcoma invasion and metastasis.

PURPOSE: Notch signaling is an important mediator of growth and survival in several cancer types, with Notch pathway genes functioning as oncogenes or tumor suppressors in different cancers. However, the role of Notch in osteosarcoma is unknown. EXPERIMENTAL DESIGN: We assessed the expression of Notch pathway genes in human osteosarcoma cell lines and patient samples. We then used pharmacologic and retroviral manipulation of the Notch pathway and studied the effect on osteosarcoma cell proliferation, survival, anchorage-independent growth, invasion, and metastasis in vitro and in vivo. RESULTS: Notch pathway genes, including Notch ligand DLL1, Notch1 and Notch2, and the Notch target gene HES1, were expressed in osteosarcoma cells, and expression of HES1 was associated with invasive and metastatic potential. Blockade of Notch pathway signaling with a small molecule inhibitor of gamma secretase eliminated invasion in Matrigel without affecting cell proliferation, survival, or anchorage-independent growth. Manipulation of Notch and HES1 signaling showed a crucial role for HES1 in osteosarcoma invasiveness and metastasis in vivo. CONCLUSION: These studies identify a new invasion and metastasis-regulating pathway in osteosarcoma and define a novel function for the Notch pathway: regulation of metastasis. Because the Notch pathway can be inhibited pharmacologically, these findings point toward possible new treatments to reduce invasion and metastasis in osteosarcoma.     

A notch1 ectodomain construct inhibits endothelial notch signaling, tumor growth, and angiogenesis

Notch signaling is required for vascular development and tumor angiogenesis. Although inhibition of the Notch ligand Delta-like 4 can restrict tumor growth and disrupt neovasculature, the effect of inhibiting Notch receptor function on angiogenesis has yet to be defined. In this study, we generated a soluble form of the Notch1 receptor (Notch1 decoy) and assessed its effect on angiogenesis in vitro and in vivo. Notch1 decoy expression reduced signaling stimulated by the binding of three distinct Notch ligands to Notch1 and inhibited morphogenesis of endothelial cells overexpressing Notch4. Thus, Notch1 decoy functioned as an antagonist of ligand-dependent Notch signaling. In mice, Notch1 decoy also inhibited vascular endothelial growth factor-induced angiogenesis in skin, establishing a role for Notch receptor function in this process. We tested the effects of Notch1 decoy on tumor angiogenesis using two models: mouse mammary Mm5MT cells overexpressing fibroblast growth factor 4 (Mm5MT-FGF4) and NGP human neuroblastoma cells. Exogenously expressed FGF4 induced Notch ligand expression in Mm5MT cells and xenografts. Notch1 decoy expression did not affect tumorigenicity of Mm5MT-FGF4 cells in vitro but restricted Mm5MT-FGF4 xenograft growth in mice while markedly impairing neoangiogenesis. Similarly, Notch1 decoy expression did not affect NGP cells in vitro but disrupted vessels and decreased tumor viability in vivo. These results strongly suggest that Notch receptor signaling is required for tumor neoangiogenesis and provides a new target for tumor therapy.     

Notch3: from subtle structural differences to functional diversity

The Notch3 gene was identified, at the beginning of 90s, as the third mammalian Notch and was initially reported as being expressed in proliferating neuroepithelium. Since then, increasing evidence has demonstrated a number of structural and functional differences between Notch3 and both Notch1 and Notch2, which exhibit the highest structural similarity among the four mammalian Notch receptors. Possibly due to its more restricted tissue distribution, targeted deletion of murine Notch3 does not lead to embryonic lethality as is observed with targeted deletion of Notch1 and Notch2. However, genetic mutation, amplification and deregulated expression of Notch3 have been correlated with the disruption of cell differentiation in transgenic mice and to development of diseases in mice and humans. This review discusses the possible relationships between the structural differences and the nonredundant roles that Notch3 plays in the pathogenesis of the human disease cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy and in the regulation of murine T-cell differentiation and leukemogenesis.     

Gain-of-function mutations and copy number increases of Notch2 in diffuse large B-cell lymphoma

Signaling through the Notch1 receptor has a pivotal role in early thymocyte development. Gain of Notch1 function results in the development of T-cell acute lymphoblastic leukemia in a number of mouse experimental models, and activating Notch1 mutations deregulate Notch1 signaling in the majority of human T-cell acute lymphoblastic leukemias. Notch2 , another member of the Notch gene family, is preferentially expressed in mature B cells and is essential for marginal zone B-cell generation. Here, we report that 5 of 63 (~8%) diffuse large B-cell lymphomas, a subtype of mature B-cell lymphomas, have Notch2 mutations. These mutations lead to partial or complete deletion of the proline-, glutamic acid-, serine- and threonine-rich (PEST) domain, or a single amino acid substitution at the C-terminus of Notch2 protein. Furthermore, high-density oligonucleotide microarray analysis revealed that some diffuse large B-cell lymphoma cases also have increased copies of the mutated Notch2 allele. In the Notch activation-sensitive luciferase reporter assay in vitro , mutant Notch2 receptors show increased activity compared with wild-type Notch2. These findings implicate Notch2 gain-of-function mutations in the pathogenesis of a subset of B-cell lymphomas, and suggest broader roles for Notch gene mutations in human cancers. ( Cancer Sci 2009; 100: 920–926)     

Notch1信号途径在食管鳞癌细胞株EC9706的作用研究

目的：研究Notch1基因在食管癌细胞株中的表达及其对食管鳞癌细胞EC9706凋亡的影响.方法：通过免疫细胞化学检测Notch1基因在EC9706细胞中的表达.通过RT-PCR扩增Notch1基因,构建真核表达载体pcDNA3.1-Notch1,转染EC9706细胞,利用Western blotting检测转染pcDNA3.1-Notch1载体12h,24h,48h,72h的食管癌细胞株与转染空载体食管癌细胞株中Notch1的表达,并观察每一时期食管癌细胞株的凋亡情况.结果：在食管癌细胞株中Notch1基因低表达,此外,转染Notch1后的细胞株Notch1表达量与转染空载体相比有明显差异（F=80.442,P＜0.05）.经组间两两比较,实验组食管癌细胞株的Notch1的表达量在12h时比对照组食管癌细胞株的表达量显著增高（P＜0.01）,前者约为后者的4.6倍.但48h至72h时Notch1表达量实验纽与对照组食管癌细胞株无显著性差异（P＞0.05）.进一步通过倒置显微镜发现48h至72h细胞出现大量凋亡的现象.上述结果说明12h Notch1表达量的增加,使食管癌细胞EC9706中的Notch1信号途径得以激活,该途径激活后导致48h到72h时的细胞大量凋亡.结论：Notch1在食管癌细胞中的激活引起细胞大量凋亡,提示Notch1基因有可能成为治疗食管癌的新靶点.     

T细胞淋巴瘤中Notch1基因突变及其蛋白表达的研究

 目的　探讨Notch1蛋白表达及基因突变在T细胞淋巴瘤发病中的作用。方法　采用免疫组织化学和基因测序法检测30例T细胞淋巴瘤组织中Notch1蛋白的表达及Notch1基因26、27号外显子（HD）和34号外显子（PEST）突变情况。另取l0例淋巴结反应增生标本作为对照。结果　30例T细胞淋巴瘤中,21例（70.0 %）Notch1蛋白表达阳性。17例（56.7 %）Notch1基因发生突变,其中,8例突变发生在Notch1基因的HD结构域,6例发生在Notch1基因的PEST结构域,3例在HD和PEST结构域均发生突变。突变方式有插入、片段缺失、无义突变和错义突变。对照组有1例（10.0 %）Notch1蛋白表达阳性,Notch1基因无突变。结论　Notch1蛋白表达可能与Notch1基因突变有关,Notch1蛋白表达和基因突变可能与T细胞淋巴瘤的发生有关。