肿瘤干细胞放射抗拒的相关研究进展

为了解肿瘤干细胞在放射抗拒中的作用及其相关机制的研究进展。应用pubmed和CNKI数据库检索系统,以"肿瘤干细胞"、"放射抗拒"、"细胞凋亡"等为关键词,检索相关文献。收入标准为:肿瘤干细胞与放射抗拒之间的关系。根据相关标准分析相关文献。肿瘤干细胞是导致放射治疗失败的主要细胞,其放射抗拒机制包括细胞存活和凋亡相关信号转导通路的异常激活、肿瘤微环境对肿瘤干细胞的保护作用、肿瘤干细胞放射损伤的自我修复和大多数的肿瘤干细胞处于静止期。肿瘤干细胞是导致放疗失败的主要因素之一,对于放射抗拒的研究有助于展开针对肿瘤干细胞的靶向治疗,提高放射治疗的敏感性。     

转录因子对干细胞高效定向分化为β细胞的作用

移植干细胞分化的胰岛β细胞能逆转糖尿病鼠的高血糖症,为细胞疗法临床应用于糖尿病治疗提供依据。但如何诱导干细胞高效、定向分化为具有分泌功能的胰岛β细胞,仍是当今世界难题。就影响干细胞分化为胰岛β细胞的关键转录因子PDX-1、Ngn3、NeuroD1、MafA的作用及机制进行综述,为干细胞高效定向分化提供新的思路。     

间充质干细胞来源细胞外囊泡对肺部疾病作用研究进展

细胞外囊泡(extracellular vesicles, EVs)是细胞自然分泌的脂质囊泡结构,在生理和病理过程中发挥信息交流作用。间充质干细胞(mesenchymal stromal cell, MSCs)是一种来源广泛的多能基质干细胞,其强大的再生潜能及免疫调节能力在肺部疾病的修复和治疗中显示出广阔前景。间充质干细胞来源细胞外囊泡(mesenchymal stromal cell extracellular vesicles, MSCs-EV)具有类似MSCs的功能特性,其携带的多种活性因子在肺部组织、肺微环境及肺部疾病中展现出良好治疗效果。主要总结了MSCs及MSCs-EV生物特性,深入讨论了MSCs-EV在肺部疾病中的作用机制及临床应用价值。     

SP细胞研究进展

SP（side population）胞是细胞群体中极少的一部分,它们可将进入细胞核的荧光染料排出胞外,在荧光显微镜下观察或流式细胞检测时表现为不着色,故称为SP细胞。已发现SP细胞和干细胞具有很多共性,且与肿瘤干细胞很相似。对SP细胞及其性质、分离方法、用途,以及SP细胞与肿瘤干细胞的关系等进行了简要阐述。     

脂肪来源干细胞通过Wnt/β-catenin通路调控前列腺增生上皮BPH-1细胞的增殖和凋亡

为了探讨脂肪来源干细胞对前列腺增生上皮BPH-1细胞增殖和凋亡的影响及分子机制,本研究从人体脂肪组织中分离脂肪来源干细胞并通过流式细胞术鉴定细胞表面标志物,将实验分为2组:对照组和脂肪来源干细胞共培养组。采用Transwell进行共培养,脂肪干细胞与前列腺增生上皮BPH-1细胞共培养组中两者比例为1:1,对照组中不含脂肪干细胞。CCK8检测前列腺增生上皮BPH-1细胞活力;羟脯氨酸法检测前列腺增生上皮细胞胶原合成能力;流式检测前列腺增生上皮细胞凋亡率;Western blotting检测前列腺增生上皮细胞Wnt3a、Bcl2和β-catenin蛋白表达水平。流式细胞仪检测结果,显示酶消化法能够从脂肪组织中分离出脂肪干细胞。人脂肪来源干细胞与前列腺增生上皮BPH-1细胞共培养能够显著抑制前列腺增生上皮BPH-1细胞的增殖能力,羟脯氨酸检测结果表明,脂肪干细胞能够显著抑制前列腺增生上皮BPH-1细胞胶原合成,流式检测结果显示脂肪干细胞能够显著促进前列腺增生上皮BPH-1细胞的凋亡,Western blotting检测显示脂肪干细胞能够显著抑制前列腺增生上皮BPH-1细胞Wnt3a、Bcl2和β-catenin蛋白表达。本研究的初步结论表明:脂肪来源干细胞通过抑制Wnt/β-catenin通路抑制前列腺增生上皮BPH-1细胞增殖。     

长非编码RNA HOTAIR调控胃癌细胞SGC-7901来源肿瘤干细胞样细胞

肿瘤干细胞样细胞具有自我更新、无限增殖和多向分化能力,且受到长非编码RNA（long non-coding RNAs, lncRNAs）的调控。长非编码RNA HOTAIR在人胃癌细胞中表达升高,且具有调控功能。但目前对其在胃癌干细胞样细胞中的功能尚无研究。本研究的目的是探讨胃癌肿瘤干细胞中HOTAIR对肿瘤恶性行为的调控作用。本研究采用无血清培养基在补充细胞因子条件下培养SGC-7901细胞,获得悬浮生长的肿瘤干细胞样细胞微球,检测微球细胞的表面特征因子CD44、CD24及HOTAIR的表达量变化;并通过CCK-8、流式细胞分析及ELISA等技术探讨了HOTAIR对肿瘤干细胞样细胞功能调控作用。结果表明,无血清培养基中获得的肿瘤干细胞样细胞具有自我更新能力,其可连续传代细胞微球的比率为4.75%±0.76%;RT-qPCR检测显示,相对于SGC-7901细胞,肿瘤干细胞样细胞中的HOTAIR表达量明显升高;通过慢病毒干扰技术发现,HOTAIR干扰抑制了HLA-G蛋白分泌、促进肿瘤干细胞样细胞的细胞周期推进、细胞增殖和自我更新能力维持。本研究提示,胃癌细胞系SGC-7901中的肿瘤干细胞样细胞中HOTAIR表达量升高,并可能通过促进肿瘤干细胞样细胞干性调控肿瘤恶性行为。     

上皮肿瘤始于干细胞

人类肿瘤大约90％以上源自于上皮。上皮干细胞是唯一长期存在于上皮组织的细胞,可积累多次突变生成肿瘤。所以,人们认为肿瘤多起源于正常干细胞。然而,目前研究中关于上皮肿瘤干细胞及其与正常上皮干细胞的关系了解甚少。现综述近年来有关上皮干细胞和肿瘤发生的关系及其调控机制方面的研究进展。     

肌卫星细胞研究进展

骨骼肌中的卫星细胞,长期以来就被认为是出生后骨骼肌生长、修复和维持的单能成肌干细胞。近年研究发现,卫星细胞与内皮细胞共同起源于胚胎血管祖细胞,且成年骨骼肌中存在多能干细胞,这些肌源多能干细胞在适当的微环境中具有多向分化潜能。这将为治疗包括帕金森病在内的多种临床退行性疾病提供自体干细胞的新来源。本文对肌卫星细胞的起源、增殖和成肌分化的分子调节机制,以及肌卫星细胞的多能干细胞潜能等方面的研究进展进行了综述。     

乳腺癌干细胞分选及相关信号通路研究进展

肿瘤干细胞是指存在于肿瘤组织中的具有干细胞特性,即能够多向分化和自我更新的一类细胞群。随着肿瘤干细胞概念的提出,乳腺癌干细胞成为当今科研领域的一个研究热点。因此,了解如何分选乳腺癌干细胞及如何维持其"干性"对治疗及预防乳腺癌具有至关重要的意义。主要从乳腺癌干细胞分选、相关信号通路、上皮-间充质转换(EMT)等方面进行综述。     

干细胞诱导分化为胰岛素分泌细胞的研究现状

胰腺或胰岛细胞移植是目前治疗Ⅰ型糖尿病和部分Ⅱ型糖尿病效果最理想的方法,但因来源组织短缺及需要终生服用免疫抑制剂等问题限制了它的广泛应用.利用胰腺或胰腺外的多能干细胞产生胰岛样细胞有望克服上述问题而用于治疗糖尿病.本文就将干细胞诱导分化为胰岛样细胞中所用的重要的转录因子和可溶性诱导因子及其作用以及胰岛素分泌细胞的来源做一综述.     

Detection of a novel stem cell probably involved in normal turnover of the lung airway epithelium

Regeneration of the lung airway epithelium after injury has been extensively studied. In contrast, analysis of its turnover in healthy adulthood has received little attention. In the classical view, this epithelium is maintained in the steady‐state by the infrequent proliferation of basal or Clara cells. The intermediate filament protein nestin was initially identified as a marker for neural stem cells, but its expression has also been detected in other stem cells. Lungs from CD1 mice at the age of 2, 6, 12, 18 or 24 months were fixed in neutral‐buffered formalin and paraffin‐embedded. Nestin expression was examined by an immunohistochemical peroxidase‐based method. Nestin‐positive cells were detected in perivascular areas and in connective tissue that were in close proximity of the airway epithelium. Also, nestin‐positive cells were found among the cells lining the airway epithelium. These findings suggest that nestin‐positive stem cells circulate in the bloodstream, transmigrate through blood vessels and localize in the lung airway epithelium to participate in its turnover. We previously reported the existence of similar cells able to differentiate into lung chondrocytes. Thus, the stem cell reported here might be a bone marrow‐derived mesenchymal stem cell (BMDMSC) able to generate several types of lung tissues. In conclusion, our findings indicate that there exist a BMDMSC in healthy adulthood that participates in the turnover of the lung airway epithelium. These findings may improve our knowledge about the lung stem cell biology and also provide novel approaches to therapy for devastating pulmonary diseases.     

隐窝干细胞和结肠癌的发生

肠道上皮细胞系是人体细胞更新最快的组织,更新速率甚至远远超过了肿瘤组织,这种无与伦比的更新速率如同一把双刃剑,一方面可以迅速的更新和修复肠粘膜,另一方面却大大增加了肠道细胞恶化的易感性。Wnt信号、Notch信号、BMP信号都参与了隐窝干细胞增殖分化的平衡,它们中任何一个组分发生突变或异常都将会导致结肠癌的发生。结肠癌的发生很可能是肠隐窝干细胞分化受阻的结果,隐窝干细胞是致瘤起始事件或突变的标靶。     

BMP signaling and stem cell regulation

Stem cells play an essential role in cellular specialization and pattern formation during embryogenesis and in tissue regeneration in adults. This is mainly due to a stem cell's ability to replenish itself (self-renewal) and, at the same time, produce differentiated progeny. Realization of these special stem cell features has changed the prospective of the field. However, regulation of stem cell self-renewal and maintenance of its potentiality require a complicated regulatory network of both extracellular cues and intrinsic programs. Understanding how signaling regulates stem cell behavior will shed light on the molecular mechanisms underlying stem cell self-renewal. In this review, we focus on comparing the progress of recent research regarding the roles of the BMP signaling pathway in different stem cell systems, including embryonic stem cells, germline stem cells, hematopoietic stem cells, and intestinal stem cells. We hope this comparison, together with a brief look at other signaling pathways, will bring a more balanced view of BMP signaling in regulation of stem cell properties, and further point to a general principle that self-renewal of stem cells may require a combination of maintenance of proliferation potential, inhibition of apoptosis, and blocking of differentiation.     

干细胞巢研究进展

干细胞巢即干细胞周围的微环境构成,一般包括干细胞的相邻细胞、粘附分子及基质等,但不同的干细胞有不同的巢结构。干细胞巢通过不同信号途径调控着干细胞的行为,使干细胞的自我更新和分化处于平衡状态。根据近年来有关干细胞巢的研究,本文从果蝇生殖系干细胞巢、哺乳动物造血干细胞巢、肠干细胞巢、毛囊表皮干细胞巢和神经干细胞巢等五个系统分别综述了干细胞巢的构成及其对干细胞的调节作用,探讨了干细胞巢作用于干细胞的内在机制。     

Novel method for isolation of murine clara cell secretory protein-expressing cells with traces of stemness

Clara cells are non-ciliated, secretory bronchiolar epithelial cells that serve to detoxify harmful inhaled substances. Clara cells also function as stem/progenitor cells for repair in the bronchioles. Clara cell secretory protein (CCSP) is specifically expressed in pulmonary Clara cells and is widely used as a Clara cell marker. In addition CCSP promoter is commonly used to direct gene expression into the lung in transgenic models. The discovery of CCSP immunoreactivity in plasma membranes of airway lining cells prompted us to explore the possibility of enriching Clara cells by flow cytometry. We established a novel and simple method for the isolation of CCSP-expressing cell Clara cells using a combination of mechanical and enzymatic dissociation followed by flow cytometry sorting technology. We showed that ～25% of dissociated cells from whole lung expressed CCSP. In the resulting preparation, up to 98% of cells expressed CCSP. Notably, we found that several common stem cell markers including CD44, CD133, Sca-1 and Sox2 were expressed in CCSP(+) cells. Moreover, CCSP(+) cells were able to form spheroid colonies in vitro with 0.97‰ efficiency. Parallel studies in vivo confirmed that a small population of CCSP(-)expressing cells in mouse airways also demonstrates stem cell-like properties such as label retention and harboring rare bronchioalveolar stem cells (BASCs) in terminal bronchioles (TBs). We conclude that CCSP(+) cells exhibit a number of stem cell-like features including stem cell marker expression, bronchosphere colony formation and self-renewal ability. Clara cell isolation by flow cytometry sorting is a useful method for investigating the function of primary Clara cells in stem cell research and mouse models.     

Pulmonary epithelial stem cells

Classically, the stem/progenitor cells of the pulmonary epithelium are considered to be the basal and mucous cells of the proximal airways, Clara cells in the bronchioles and type II pneumocytes in the alveoli. Recent data suggest that there is a variant of Clara cells, lying in pulmonary neuroendocrine bodies, that meets several stem cell criteria and that type II pneumocytes exist in at least two populations, one of which is more resistant to injury. However, a complete revision of our understanding of pulmonary stem cell biology is underway as a result of the discovery of pulmonary epithelium derived from blood-borne cells. In addition, the existence in the lung of a 'universal' pluripotent cell has long been speculated upon and now some initial evidence has emerged with the identification of a spore-like cell that can differentiate in vitro to bronchiolar tissue.     

Niche regulation of corneal epithelial stem cells at the limbus

Among all adult somatic stem cells,those of the corneal epithelium are unique in their exclusive location in a definedlimbai structure termed Palisades of Vogt.As a result,surgical engraftment oflimbal epithelial stem cells with or withoutex vivo expansion has long been practiced to restore sights in patients inflicted with limbal stem cell deficiency.Neverthe-less,compared to other stem cell examples,relatively little is known about the limbal niche,which is believed to play apivotal role in regulating self-renewal and fate decision of limbal epithelial stem cells.This review summarizes relevantliterature and formulates several key questions to guide future research into better understanding of the pathogenesis oflimbal stem cell deficiency and further improvement of the tissue engineering of the corneal epithelium by focusing onthe limbal niche.     

13 years of cultured limbal epithelial cell therapy: a review of the outcomes

The cornea is the clear tissue at the front of the eye which enables the transmission of light to the retina for normal vision. The surface of the cornea is composed of an epithelium which is renewed by stem cells located at the periphery of the cornea, a region known as the limbus. These limbal stem cells can become deficient as a result of various diseases of the eye's surface, resulting in the blinding disease of limbal stem cell deficiency. The treatment of this disease is often difficult and complex. In 1997, it was proposed that a small amount of limbal tissue containing limbal stem cells could be culture expanded and then transplanted. Since then various case reports and case series have been reported showing promising results. Here, we review the outcomes of this procedure over the past 13 years with the aim of highlighting the best culture and surgical techniques to date.     

A Notch positive feedback in the intestinal stem cell niche is essential for stem cell self‐renewal

The intestinal epithelium is the fastest regenerative tissue in the body, fueled by fast‐cycling stem cells. The number and identity of these dividing and migrating stem cells are maintained by a mosaic pattern at the base of the crypt. How the underlying regulatory scheme manages this dynamic stem cell niche is not entirely clear. We stimulated intestinal organoids with Notch ligands and inhibitors and discovered that intestinal stem cells employ a positive feedback mechanism via direct Notch binding to the second intron of the Notch1 gene. Inactivation of the positive feedback by CRISPR/Cas9 mutation of the binding sequence alters the mosaic stem cell niche pattern and hinders regeneration in organoids. Dynamical system analysis and agent‐based multiscale stochastic modeling suggest that the positive feedback enhances the robustness of Notch‐mediated niche patterning. This study highlights the importance of feedback mechanisms in spatiotemporal control of the stem cell niche.     

肺腺癌干细胞表达小细胞肺癌相关抗原的实验研究

肿瘤干细胞（cancerstem cells,csc）是指一类具有自我更新（self-renewal）能力的未分化细胞。在肺腺癌中,csc的自我更新调控机制类似胚胎干细胞,即高表达OCT4、Nanog和Sox2}潜能基因,但目前对其表型特征尚存争议。该文采用成球试验（sphere—formingassay）AkSPC—A1细胞株中富集CSC后进行分子表型分析。结果显示,此类肺球体细胞（pulmospheres）同时表达肺脏近端和远端呼吸上皮的多个谱系（1ineage）标志,包括纤毛柱状细胞标志FoxJl、非纤毛柱状细胞（即Clara细胞）标志CCSP、肺神经肉分泌细胞标志GRP、II型肺泡细胞标志SP-C及其转录调控因子TTF-1。这些肺球体细胞也能够被3株小细胞肺癌特异性单抗（2F7、483和E6）所识别。通过基因沉默技术使得肺球体细胞中OCT4表达转阴后,上述标志（除E6P外）均消失。研究结果揭示,肺癌CSC具有肺脏呼吸上皮多潜能细胞的表型特征。此外,初步研究结果发现,中药冬虫夏草（Hirsutella Hepialid of Cordyceps Sinensis）的被毛孢菌丝体中含有新颖抗癌成分,能够显著遏制肺球体细胞增殖,提示对其进行分离鉴定,将是研制开发肺癌CSC靶向药物的一个发展方向。