Notch信号通路与生殖干细胞研究进展

Notch信号通路是一个在进化中高度保守的信号通道,具有调控细胞增殖、分化及凋亡的作用。近年来,随着研究的不断深入,发现Notch信号通路与生殖干细胞的增殖分化及干细胞微环境的作用机理密切关联,Notch信号通路在生殖系统发育及疾病治疗中的作用机制逐渐引起人们的广泛关注。该文综合论述了Notch信号通路的生理特性及功能,重点阐述Notch信号通路在精原干细胞、卵巢生殖干细胞及生殖干细胞微环境系统中的调控机制。     

Notch信号通路对相关疾病调控作用的研究进展

Notch信号通路是保守的细胞间信号通路,其在胚胎形成和器官发生过程中对于控制干细胞和祖细胞的增殖、分化发挥着至关重要的作用,是发育生物学、细胞生物学、免疫学及血液学等多个领域的研究热点之一。近来研究发现,多种疾病的发生与Notch信号异常有关。本文就Notch信号通路的组成以及在神经病理性疼痛、神经退行性行疾病、脑损伤、肿瘤等的调节作用机制的进行综述。     

Notch的结构、功能和相关信号通路

Notch是广泛存在于细胞表面介导细胞间信号传递的一类高度保守的受体蛋白。Notch信号通路是通过细胞间相互作用来调节生物体生长发育的一个十分保守的信号通路。Notch信号通路在脊椎动物和无脊椎动物的发育过程中,对细胞命运的决定、神经系统的发育、器官的形成及体节的发生都有重要的作用。特别是在免疫系统和肿瘤发生中也起着极为重要的作用。目前,Notch信号已经成为发育生物学、细胞生物学、免疫学及血液学等多个领域的研究热点之一。本文就Notch信号通路的组成、调节作用机制及该通路与个体发育之间的联系作一综述。     

Notch信号通路调控猕猴胚胎干细胞的胆管样细胞分化(英文)

猕猴胚胎干细胞(rhesus monkey embryonic stem(rES))与人胚胎干细胞有相似的生物学特性,因此是理想的临床前研究的替代模型。Notch信号通路在胆管及胆管上皮细胞的形成中有重要的作用,然而,有关Notch信号通路在ES细胞的胆向分化中的作用了解甚少。该实验以rES为模型,对Notch信号通路对ES细胞的胆向分化过程中的作用进行了较为系统的研究。rES在细胞因子ActivinA诱导作用下产生约80%的限定性内胚层细胞。以Matrigel作为细胞外基质,在含BMP4和FGF1的无血清培养体系中继续诱导5～7d,rES细胞来源的限定性内胚层细胞分化产生约胆管样细胞。分化的细胞表达胆管细胞的特异性蛋白((CK7、CK18、CK19、CK20和OV-6)及基因(GSTPi、IB4和HNF1β)。在胆管样细胞的分化过程中检测到了Notch1和Notch2基因及下游信号分子hes1和hes5的表达。用Notch抑制剂L-685458处理分化过程中的细胞可导致Notch1和Notch2基因及下游信号分子hes1和hes5的表达下降,同时CK19阳性的胆管样细胞分化比率也从90%下降至约20%。这一...     

靶向肝癌干细胞的肿瘤治疗进展

肝癌是最常见的五大癌症之一,也是患者死亡的重要癌症类型之一。传统方法对治疗早期肝癌取得了一定的进展,但是癌症的复发、转移和耐药仍未得到根本解决,而这些现象可通过癌症干细胞(cancer stem cells,CSCs)理论进行解释。原发性肝癌主要包括肝细胞癌(hepatocellular carcinoma,HCC)和肝内胆管癌(intrahepatic cholangiocarcinoma,ICC),目前认为其可能部分起源于肝癌干细胞。与肝癌干细胞有关的Wnt/β-catenin、TGF-β、Notch和Hedgehog等信号通路和Ep CAM、Lin28和mi R-181等分子,在体内外调节肝癌干细胞活性,并可用以设计预防或治疗癌症的分子靶点。然而,肝癌和肝癌干细胞涉及一个复杂的发生和调节机制,存在相互干扰和冗余的信号通路,因此针对单个分子或途径的治疗效果有限。该文综述了肝癌干细胞与肝癌发生的进展及其相关的信号通路与关键分子,与针对肝癌干细胞治疗的新策略。     

骨髓间充质干细胞分化为心肌细胞过程中Notch表达的研究

目的研究骨髓间充质干细胞分化为心肌细胞过程中Notch表达的研究。方法用密度梯度离心法分离培养犬骨髓间充质干细胞,按照酶法及差速贴壁法分离培养心肌细胞。观察干细胞增殖及传代情况。单独培养的干细胞为对照组,实验组将骨髓间充质干细胞与心肌细胞共培养,用RT-PCR、免疫细胞化学、MTT等方法检测干细胞分化为心肌细胞的情况,及干细胞在增殖与分化为心肌细胞过程中Notch信号系统的表达情况。结果骨髓间充质干细胞呈梭形、旋涡样生长,增殖及传代能力强,并可诱导分化为心肌样细胞,免疫荧光示心肌细胞标志物的表达。RT-PCR及免疫细胞化学显示实验组有Notch信号通路受体及配体的表达,而对照组表达微弱。结论骨髓间充质干细胞在增殖及分化过程中存在Notch信号通路,在干细胞分化为心肌细胞过程中Notch信号系统的表达上调。     

肿瘤干细胞研究进展

在过去的十年中,肿瘤干细胞（cancer stem cell／tumor—initiating cell,CSC／TIC）虽然受到广泛重视,但也是争论的焦点。如何正确认识CSCs假说,以及CSCs的生物学特点和CSCs的治疗应用这些问题都存在巨大的争议。该文对CSCS的起源、分离鉴定的方法,以及信号通路、微环境等对cSCS的调控关系,肿瘤的最佳治疗途径等问题进行综述。     

Notch信号通路对神经干细胞增殖分化的作用

神经干细胞作为一种具有自我更新能力和多向分化潜能的细胞,它的增殖和分化受到多种源于自身或外在、邻近或远程细胞信号通路的调控,各种细胞因子及胞间通讯在神经干细胞的增殖和分化中发挥着重要的作用。近年来的多种研究表明,Notch信号通路正是这样一种可以通过相邻细胞的配体与受体相互作用,从而传递信号,进一步发挥其生物学功能的重要信号通路。该通路参与了神经干细胞维持自我形态及向多种具有不同功能的神经细胞分化的过程．对于研究神经干细胞的增殖和分化具有巨大的意义。该文将就当前Notch信号通路对神经干细胞增殖分化影响的相关研究进行简要综述。     

心脏干细胞研究新进展

随着近年干细胞的研究发展,心脏中心脏干细胞(CSCs)被证实存在,并发现CSCs具有自我更新及多向分化能力,负责维持心脏内环境稳态,许多学者已经从CSCs着手研究治疗终末期心脏病的新途径。本文就CSCs以及其为基础的心脏病治疗进展作一综述,尤其对中药诱导CSCs在治疗心脏病中的前景进行展望。     

Notch信号传导通路相关疾病的研究进展

Notch信号传导通路是影响细胞命运决定的重要通路之一,相邻细胞间通过Notch受体传递信号可以调节包括干细胞在内的多种细胞的分化、增殖和凋亡,影响器官形成和形态发生.Notch信号传导通路中某些分子的基因突变与多种疾病的发生发展有关.在深入研究Notch信号传导通路的基础上,以其作为靶点设计药物,对于治疗包括肿瘤、CADASIL等遗传性疾病在内的相关疾病,或发展干细胞医疗技术治疗阿尔茨海默症(Alzheimer!sdisease,AD)、帕金森病、糖尿病等细胞组织功能减退或受损性疾病具有重要的科学意义和应用价值.     

Constitutive Activation of Signal Transducer and Activator of Transcription 3 (STAT3) and Nuclear Factor κB Signaling in Glioblastoma Cancer Stem Cells Regulates the Notch Pathway

Malignant gliomas are locally aggressive, highly vascular tumors that have a dismal prognosis, and present therapies provide little improvement in the disease course and outcome. Many types of malignancies, including glioblastoma, originate from a population of cancer stem cells (CSCs) that are able to initiate and maintain tumors. Although CSCs only represent a small fraction of cells within a tumor, their high tumor-initiating capacity and therapeutic resistance drives tumorigenesis. Therefore, it is imperative to identify pathways associated with CSCs to devise strategies to selectively target them. In this study, we describe a novel relationship between glioblastoma CSCs and the Notch pathway, which involves the constitutive activation of STAT3 and NF-κB signaling. Glioma CSCs were isolated and maintained in vitro using an adherent culture system, and the biological properties were compared with the traditional cultures of CSCs grown as multicellular spheres under nonadherent culture conditions. Interestingly, both adherent and spheroid glioma CSCs show constitutive activation of the STAT3/NF-κB signaling pathway and up-regulation of STAT3- and NF-κB-dependent genes. Gene expression profiling also identified components of the Notch pathway as being deregulated in glioma CSCs, and the deregulated expression of these genes was sensitive to treatment with STAT3 and NF-κB inhibitors. This finding is particularly important because Notch signaling appears to play a key role in CSCs in a variety of cancers and controls cell fate determination, survival, proliferation, and the maintenance of stem cells. The constitutive activation of STAT3 and NF-κB signaling pathways that leads to the regulation of Notch pathway genes in glioma CSCs identifies novel therapeutic targets for the treatment of glioma.     

Blocking the NOTCH pathway can inhibit the growth of CD133-positive A549 cells and sensitize to chemotherapy

Cancer stem cells (CSCs) are believed to play an important role in tumor growth and recurrence. These cells exhibit self-renewal and proliferation properties. CSCs also exhibit significant drug resistance compared with normal tumor cells. Finding new treatments that target CSCs could significantly enhance the effect of chemotherapy and improve patient survival. Notch signaling is known to regulate the development of the lungs by controlling the cell-fate determination of normal stem cells. In this study, we isolated CSCs from the human lung adenocarcinoma cell line A549. CD133 was used as a stem cell marker for fluorescence-activated cell sorting (FACS). We compared the expression of Notch signaling in both CD133+ and CD133− cells and blocked Notch signaling using the γ-secretase inhibitor DAPT (GSI-IX). The effect of combining GSI and cisplatin (CDDP) was also examined in these two types of cells. We observed that both CD133+ and CD133− cells proliferated at similar rates, but the cells exhibited distinctive differences in cell cycle progression. Few CD133+ cells were observed in the G₂/M phase, and there were half as many cells in S phase compared with the CD133− cells. Furthermore, CD133+ cells exhibited significant resistance to chemotherapy when treated with CDDP. The expression of Notch signaling pathway members, such as Notch1, Notch2 and Hes1, was lower in CD133+ cells. GSI slightly inhibited the proliferation of both cell types and exhibited little effect on the cell cycle. The inhibitory effects of DPP on these two types of cells were enhanced when combined with GSI. Interestingly, this effect was especially significant in CD133+ cells, suggesting that Notch pathway blockade may be a useful CSC-targeted therapy in lung cancer.     

Regulation of angiogenesis via Notch signaling in breast cancer and cancer stem cells

Breast cancer angiogenesis is elicited and regulated by a number of factors including the Notch signaling. Notch receptors and ligands are expressed in breast cancer cells as well as in the stromal compartment and have been implicated in carcinogenesis. Signals exchanged between neighboring cells through the Notch pathway can amplify and consolidate molecular differences, which eventually dictate cell fates. Notch signaling and its crosstalk with many signaling pathways play an important role in breast cancer cell growth, migration, invasion, metastasis and angiogenesis, as well as cancer stem cell (CSC) self-renewal. Therefore, significant attention has been paid in recent years toward the development of clinically useful antagonists of Notch signaling. Better understanding of the structure, function and regulation of Notch intracellular signaling pathways, as well as its complex crosstalk with other oncogenic signals in breast cancer cells will be essential to ensure rational design and application of new combinatory therapeutic strategies. Novel opportunities have emerged from the discovery of Notch crosstalk with inflammatory and angiogenic cytokines and their links to CSCs. Combinatory treatments with drugs designed to prevent Notch oncogenic signal crosstalk may be advantageous over λ secretase inhibitors (GSIs) alone. In this review, we focus on the more recent advancements in our knowledge of aberrant Notch signaling contributing to breast cancer angiogenesis, as well as its crosstalk with other factors contributing to angiogenesis and CSCs.     

Dose-dependent proteomic analysis of glioblastoma cancer stem cells upon treatment with γ-secretase inhibitor

Notch signaling has been demonstrated to have a central role in glioblastoma (GBM) cancer stem cells (CSCs) and we have demonstrated recently that Notch pathway blockade by γ-secretase inhibitor (GSI) depletes GBM CSCs and prevents tumor propagation both in vitro and in vivo. In order to understand the proteome alterations involved in this transformation, a dose-dependent quantitative mass spectrometry (MS)-based proteomic study has been performed based on the global proteome profiling and a target verification phase where both Immunoassay and a multiple reaction monitoring (MRM) assay are employed. The selection of putative protein candidates for confirmation poses a challenge due to the large number of identifications from the discovery phase. A multilevel filtering strategy together with literature mining is adopted to transmit the most confident candidates along the pipeline. Our results indicate that treating GBM CSCs with GSI induces a phenotype transformation towards non-tumorigenic cells with decreased proliferation and increased differentiation, as well as elevated apoptosis. Suppressed glucose metabolism and attenuated NFR2-mediated oxidative stress response are also suggested from our data, possibly due to their crosstalk with Notch Signaling. Overall, this quantitative proteomic-based dose-dependent work complements our current understanding of the altered signaling events occurring upon the treatment of GSI in GBM CSCs.     

The role of NUMB/NUMB isoforms in cancer stem cells

Cancer stem cells (CSCs) are a subpopulation of cancer that can self-renew and differentiate into large tumor masses. Evidence accumulated to date shows that CSCs affect tumor proliferation, recurrence, and resistance to chemotherapy. Recent studies have shown that, like stem cells, CSCs maintain cells with self-renewal capacity by means of asymmetric division and promote cell proliferation by means of symmetric division. This cell division is regulated by fate determinants, such as the NUMB protein, which recently has also been confirmed as a tumor suppressor. Loss of NUMB expression leads to uncontrolled proliferation and amplification of the CSC pool, which promotes the Notch signaling pathway and reduces the expression of the p53 protein. NUMB genes are alternatively spliced to produce six functionally distinct isoforms. An interesting recent discovery is that the protein NUMB isoform produced by alternative splicing of NUMB plays an important role in promoting carcinogenesis. In this review, we summarize the known functions of NUMB and NUMB isoforms related to the proliferation and generation of CSCs.     

肿瘤干细胞生长相关的信号转导通路

肿瘤干细胞是肿瘤中存在的一小群具有自我更新和分化潜能的细胞,也是存在于肿瘤 组织中具有干细胞样能力的肿瘤细胞亚群,在肿瘤的发生、发展中起着非常重要的作用.近年来发现,肿瘤干细胞的生长调控与Wnt、Notch、Hedgehog等多种信号转导通 路有关.本文简要综述了肿瘤干细胞生长相关信号转导通路的研究进展,旨在为肿瘤干细胞研究和临床应用提供理论依据.     

Targeting HIF1α eliminates cancer stem cells in hematological malignancies

Molecular targeting of cancer stem cells (CSCs) has therapeutic potential for efficient treatment of cancer, although relatively few specific targets have been identified so far. Hypoxia-inducible factor (HIF) was recently shown to regulate the tumorigenic capacity of glioma stem cells under hypoxic conditions. Surprisingly, we found that, under normoxia, HIF1α signaling was selectively activated in the stem cells of mouse lymphoma and human acute myeloid leukemia (AML). HIF1a shRNA and HIF inhibitors abrogated the colony-forming unit (cfu) activity of mouse lymphoma and human AML CSCs. Importantly, the HIF-inhibitor echinomycin efficiently eradicated mouse lymphoma and serially transplantable human AML in xenogeneic models by preferential elimination of CSCs. Hif1α maintains mouse lymphoma CSCs by repressing a negative feedback loop in the Notch pathway. Taken together, our results demonstrate an essential function of Hif1α-Notch interaction in maintaining CSCs and provide an effective approach to target CSCs for therapy of hematological malignancies.