EWS/ATF1 expression induces sarcomas from neural crest–derived cells in mice

Clear cell sarcoma (CCS) is an aggressive soft tissue malignant tumor characterized by a unique t(12;22) translocation that leads to the expression of a chimeric EWS/ATF1 fusion gene. However, little is known about the mechanisms underlying the involvement of EWS/ATF1 in CCS development. In addition, the cellular origins of CCS have not been determined. Here, we generated EWS/ATF1-inducible mice and examined the effects of EWS/ATF1 expression in adult somatic cells. We found that forced expression of EWS/ATF1 resulted in the development of EWS/ATF1-dependent sarcomas in mice. The histology of EWS/ATF1-induced sarcomas resembled that of CCS, and EWS/ATF1-induced tumor cells expressed CCS markers, including S100, SOX10, and MITF. Lineage-tracing experiments indicated that neural crest–derived cells were subject to EWS/ATF1-driven transformation. EWS/ATF1 directly induced Fos in an ERK-independent manner. Treatment of human and EWS/ATF1-induced CCS tumor cells with FOS-targeted siRNA attenuated proliferation. These findings demonstrated that FOS mediates the growth of EWS/ATF1-associated sarcomas and suggest that FOS is a potential therapeutic target in human CCS.     

CD99在部分骨及软组织小细胞恶性肿瘤中的表达及意义

目的观察CD99在部分小细胞恶性肿瘤中的表达及意义。方法对257例骨和软组织小细胞恶性肿瘤采用EnVision二步法检测CD99的表达。结果257例中CD99在间叶性软骨肉瘤的阳性率为93.3%(14/15),在骨内EWS及软组织内EWS/PNET的阳性率为100%(97/97);在浆细胞骨髓瘤的阳性率为2.7%(2/73);在骨内原发性恶性淋巴瘤(均为B细胞型非霍奇金淋巴瘤)的阳性率为13.5%(5/37);在小细胞型骨肉瘤的阳性率为95%(17/18);在骨转移性小细胞癌的阳性率为70%(7/10);在以梭形细胞为主的单向型滑膜肉瘤的阳性率为100%(5/5);1例促结缔组织增生性小细胞肿瘤为(+);而1例软组织胚胎性横纹肌肉瘤为(-)。结论CD99可在多种小细胞恶性肿瘤中有阳性表达。此抗体在骨及软组织小细胞恶性肿瘤的鉴别诊断中特异性较差,CD99单项阳性不能作为鉴别诊断依据。     

RT-PCR法检测EWS-FLI1融合基因诊断尤文肉瘤/外周原始神经外胚层瘤

目的探讨尤文肉瘤/外周原始神经外胚层瘤(EWS/pPNET)石蜡包埋组织中EWS-FLI1融合基因表达的临床病理意义。方法采用免疫组化对1例纵隔尤文肉瘤/外周原始神经外胚层瘤进行观察,应用反转录-聚合酶链反应(RT-PCR)检测融合基因EWS-FLI1的表达。结果肿瘤由小圆细胞、卵圆形细胞及短梭形细胞构成,巢状、片状或列兵样排列,间质显著增生,未见典型菊形团结构。免疫组化显示CK、EMA和CD99弥漫强( )。RT-PCR检测出EWS-FLIl融合基因的表达。结论EWS/pPNET与促结缔组织增生性小圆细胞肿瘤(DSRCT)具有重叠的形态学和免疫组化特点,石蜡包埋组织中检测EWS-FLI1融合基因的表达可作为诊断EWS/pPNET的可靠指标。     

骨髓间充质干细胞诱导分化为神经干细胞过程中端粒酶的表达

背景:端粒酶在细胞分化及活化过程起重要作用。目的:检测骨髓间充质干细胞诱导分化为神经干细胞过程中端粒酶的表达。方法:采用PCR-ELISA端粒酶检测方法检测SD大鼠骨髓间充质干细胞传代培养前6代细胞中端粒酶的表达;将传代培养的第3代SD大鼠骨髓间充质干细胞诱导分化为神经干细胞,传代培养至第6代,检测各代细胞中端粒酶的表达。以人胚肾细胞系293细胞蛋白提取物作为阳性对照,以灭活细胞蛋白提取物为阴性对照。结果与结论:端粒酶在传代培养的前6代骨髓间充质干细胞中呈阳性表达,为阳性对照组的9.4%～30.9%,第3代表达最高;在诱导分化为神经干细胞传代培养的前5代呈阳性表达,为阳性对照组的5.4%～33.1%,第3代和第4代表达最高。说明端粒酶是细胞分化、增殖的一个重要因素。     

Wnt3a促进大鼠骨髓间充质干细胞向神经元样细胞的分化

背景:Wnt信号通路是细胞增殖分化的关键调控环节,但与骨髓间充质干细胞神经分化的联系并不十分明确.目的:寻找促进骨髓间充质干细胞向神经元样细胞分化的Wnt信号分子.方法:首先体外分离培养大鼠骨髓间充质干细胞并传代,行形态学观察,并以流式细胞学方法检测细胞表型CD44,CD9,CD34和CD45.采用碱性成纤维细胞生长因子分别联合Wnt3a或Wnt5a的方案诱导分化,应用免疫组化和反转录-聚合酶链反应方法比较Wnt3a和Wnt5a对骨髓间充质干细胞向神经元样细胞分化的影响.结果与结论:骨髓间充质干细胞为长梭形,CD9,CD44高表达,CD34,CD45低表达.Wnt3a诱导组的巢蛋白和神经元特异烯醇化酶呈阳性,而胶质纤维酸性蛋白无明显表达,诱导后细胞的活力良好.Wnt5a诱导组巢蛋白呈弱阳性表达,而神经元特异烯醇化酶及胶质纤维酸性蛋白阴性.反转录-聚合酶链反应结果显示,Wnt3a诱导组巢蛋白在诱导前后均有表达,神经元特异烯醇化酶在诱导后5 d可见明显的扩增条带,10 d后更加明显.胶质纤维酸性蛋白在诱导10 d后出现较弱的扩增条带.Wnt5a组、对照组骨髓间充质干细胞在诱导后10 d巢蛋白有微弱表达,神经元特异烯醇化酶和胶质纤维酸性蛋白几乎无表达.提示Wnt3a分子能够促进体外培养的骨髓间充质干细胞向神经元样细胞分化.     

肝癌干细胞分离及其细胞生物学特性

背景：正常干细胞和肿瘤干细胞在基因表达和依赖的细胞信号通路上应该存在不同,如何发现能选择性杀伤肿瘤干细胞的治疗手段是一个仍然需要大量研究的课题。目的：分离人肝癌细胞系肿瘤干细胞MHCC97,分析其细胞生物学特性。方法：采用流式细胞技术在人高转移肝癌细胞系 MHCC97中筛选肿瘤干细胞,分离正常人肝脏干细胞CD133-CD34-MHCC97和人肝癌细胞系肿瘤干细胞CD133＋CD34＋MHCC97,分别检测其表型、生长曲线、细胞周期和多系分化能力。结果与结论：人肝癌细胞系 CD133＋CD34＋ MHCC97肿瘤干细胞的表型为 CD133＋CD34＋,人肝癌细胞系CD133＋CD34＋ MHCC97具有与CD133-CD34- MHCC97相似的细胞曲线和生长周期,可以向上皮和内皮细胞分化,并表达相应特异性的分子标志。提示人肝癌细胞系中 CD133＋CD34＋MHCC97细胞具有肿瘤干细胞的特性,可以向内皮和上皮细胞分化,同时具有肿瘤干细胞的生物学特性,是肿瘤复发转移的根源,也是临床治疗的靶点。     

The 86-kD subunit of Ku autoantigen mediates homotypic and heterotypic adhesion of multiple myeloma cells.

Previous studies have shown that triggering multiple myeloma (MM) cells via CD40 induces IL-6-mediated autocrine growth as well as increased expression of cell surface adhesion molecules including CD11a, CD11b, CD11c, and CD18. In this study, we generated the 5E2 mAb which targets an antigen that is induced upon CD40 ligand (CD40L) activation of MM cells. Immunofluorescence, immunoprecipitation, and protein sequencing studies identified the target antigen of 5E2 mAb as the 86-kD subunit of the Ku autoantigen. We demonstrate that increased cell surface expression of Ku on CD40L-treated cells is due to migration of Ku from the cytoplasm to the cell surface membrane. Moreover, cell surface Ku on CD40L-treated MM cells mediates homotypic adhesion of tumor cells, as well as heterotypic adhesion of tumor cells to bone marrow stromal cells and to human fibronectin; and 5E2 mAb abrogates IL-6 secretion triggered by tumor cell adherence to bone marrow stromal cells. These data suggest that CD40L treatment induces a shift of Ku from the cytoplasm to the cell surface, and are the first to show that Ku functions as an adhesion molecule. They further suggest that cell surface Ku may play a role in both autocrine and paracrine IL-6-mediated MM cell growth and survival.     

星形胶质细胞瘤干细胞的体外分离、培养与鉴定

背景：肿瘤干细胞理论认为肿瘤中存在一小部分具有无限增殖潜能和自我更新能力,能够分化为成熟细胞表型的干细胞样细胞,对肿瘤发生、增殖、侵袭起关键作用。目的：建立体外分离、培养与鉴定星形胶质细胞瘤干细胞的方法。方法：采用直接培养法分离培养星形胶质细胞瘤干细胞。参照神经干细胞培养条件,进行体外培养。观察其增殖、分化并进行巢蛋白、CD133免疫细胞化学鉴定和诱导分化后神经元特异性烯醇化酶、胶质纤维酸性蛋白及O4免疫细胞化学鉴定。结果与结论：培养7-10d,可形成大量悬浮生长巢蛋白及CD133免疫阳性的神经球,经诱导分化后细胞呈神经元特异性烯醇化酶、胶质纤维酸性蛋白或O4免疫阳性。提示星形胶质细胞瘤中存在具有神经干细胞特性的肿瘤干细胞。CD133和巢蛋白是星形胶质细胞瘤干细胞重要的表面标记,可以用于星形胶质细胞瘤干细胞的分离。     

CD99 as surface anchor for human islet endocrine cell purification

Rat and human beta cell proteomes were quantified by liquid chromatography–mass spectrometry/mass spectrometry (LC‐MS/MS), searching for cell surface markers. In human beta cells, CD99 (cluster of differentiation 99) was ranked among the plasma membrane proteins that combine a high molar abundance with a relative degree of selectivity for the endocrine cells of the islets of Langerhans. Therefore, the applicability of CD99 as anchor for islet endocrine cell purification was investigated. The CD99 gene and protein expression were studied using microarray, LC‐MS/MS, western blotting, flow cytometry and immunofluorescence, and a protocol was developed for magnetic bead‐mediated beta cell enrichment from human pancreas digests using available anti‐CD99 antibodies. In human, but not in rat, CD99 protein and mRNA were abundantly expressed by islet endocrine cells but undetectable in exocrine pancreas. The extracellular CD99 epitopes appeared to be trypsin‐resistant, enabling the binding of anti‐CD99 antibodies to an insulin+/TSQ+ cell subset and efficient coupling of magnetic beads for positive selection of CD99+ cells. A MACS‐CD99 purification of human pancreas fractions with low endocrine purity consistently yielded a fourfold enrichment of insulin+/TSQ+ cells and formation of viable and functional endocrine aggregates after 24 h of culture. It is concluded that CD99 is a human beta cell surface marker that, by virtue of its high molar abundance and resistance to tryptic digestion, can be used as anchor for upscalable magnetic bead‐mediated islet endocrine cell purification. Copyright © 2016 John Wiley & Sons, Ltd.     

CD27 signaling on chronic myelogenous leukemia stem cells activates Wnt target genes and promotes disease progression

Chronic myelogenous leukemia (CML) results from a chromosomal translocation in hematopoietic stem or early progenitor cells that gives rise to the oncogenic BCR/ABL fusion protein. Clinically, CML has a chronic phase that eventually evolves into an accelerated stage and blast crisis. A CML-specific immune response is thought to contribute to the control of disease. Whether the immune system can also promote disease progression is not known. In the present study, we investigated the possibility that the TNF receptor family member CD27 is present on leukemia stem cells (LSCs) and mediates effects of the immune system on CML. In a mouse model of CML, BCR/ABL+ LSCs and leukemia progenitor cells were found to express CD27. Binding of CD27 by its ligand, CD70, increased expression of Wnt target genes in LSCs by enhancing nuclear localization of active β-catenin and TRAF2- and NCK-interacting kinase (TNIK). This resulted in increased proliferation and differentiation of LSCs. Blocking CD27 signaling in LSCs delayed disease progression and prolonged survival. Furthermore, CD27 was expressed on CML stem/progenitor cells in the bone marrow of CML patients, and CD27 signaling promoted growth of BCR/ABL+ human leukemia cells by activating the Wnt pathway. Since expression of CD70 is limited to activated lymphocytes and dendritic cells, our results reveal a mechanism by which adaptive immunity contributes to leukemia progression. In addition, targeting CD27 on LSCs may represent an attractive therapeutic approach to blocking the Wnt/β-catenin pathway in CML.     

Two different functions for CD44 proteins in human myelopoiesis.

CD44 is important during myelopoiesis, although the contributions of variant CD44 proteins are unclear. We show here that in human long-term bone marrow culture antibodies recognizing a CD44 NH2-terminal epitope (mab 25-32) or a CD44v6 epitope (mab VFF18) inhibit myelopoiesis. However, mab 25-32 but not mab VFF18 affects myeloid colony formation. These data suggest that an early precursor cell compartment is the target for the 25-32 antibody, whereas the mab VFF18 targets later stages in myelopoiesis. Since the bulk of hemopoietic precursor cells are negative for the v6 epitope and only a minor subset of myeloid cells express the v6 epitope, we have used several human myeloid progenitor cell lines to unravel the function of different CD44 proteins. These cell lines produce variant CD44 proteins, predominantly a new variant CD44v4-v10, when stimulated towards myeloid differentiation. Features that can be acquired by the expression of CD44v4-v10 are an increased hyaluronate (HA) and a de novo chondroitin sulphate A (CS-A) binding. Although, the expression of CD44v4-v10 per se is necessary for HA and CS-A binding, the protein backbone seems to require appropriate glycosylation. HA binding results in CD44-mediated cellular self-aggregation and adhesion to the stromal cell line MS-5. In summary, our data suggest that different CD44 proteins are important for at least two different steps in myelopoiesis.     

TNF-α通过ERK信号通路刺激骨髓间充质干细胞表达VCAM-1

本研究目的在于探讨TNF-α对人骨髓间充质干细胞（bonemarrowmesenchymalstemcells,BMMSC）血管细胞黏附分子．1（vascularcelladhesionmolecule1,VCAM-1）表达的影响及与ERK信号通路的关系。应用密度梯度离心法结合贴壁培养法分离人BMMSC,并对其进行表面抗原表达及诱导分化鉴定。用不同浓度的TNF-α刺激BMMSC,流式细胞术检测其表面VCAM-1表达及ERK信号通路抑制剂U0126对BMMSCVCAM-1表达的影响,用Westernblot检测ERK通路活性的变化。结果表明,分离培养的BMMSC表达CD29、CD69、CD44、CDl05,不袁达CD34、CD45;BMMSC可诱导分化为成骨细胞及脂肪细胞;BMMSC膜上的VCAM-1表达随着TNF-α浓度的增加而增加;经U0126预处理后TNF-α刺激的BMMSC膜上的VCAM-1表达减少;TNF—α增加BMMSCERK信号通路的活化程度,U0126抑制TNF-α对ERK活性的作用。结论：TNF-α可能通过ERK信号通路刺激MSC表扶VCAM-1。     

音猬因子诱导恒河猴骨髓间质干细胞向神经元样细胞的分化与维甲酸方案比较其信号分子表达变化的意义

背景:近来研究发现在神经发育过程中,神经干细胞的分化受到来自周围微环境中诸多调控因子的作用,其中音猬因子是神经胚胎发育过程中关键性的诱导信号,有望作为一种有效的诱导剂调节神经细胞的分化.目的:探讨音猬因子诱导恒河猴骨髓间质干细胞向神经元样细胞分化过程中的信号分子表达变化.方法:常规密度梯度离心法分离培养恒河猴骨髓间质干细胞,诱导组加入含FGF2、B27、胎牛血清的L-DMEM预诱导24 h撤离血清后,分别加入含0.5 μmol/L维甲酸或400 μmol/L音猬因子的DMEM诱导8 d,以未诱导的细胞作为对照组.经神经元烯醇化酶荧光标记后,流式细胞仪筛选阳性细胞,应用RT-PCR与Western-blot法检测音猬因子和维甲酸诱导的细胞膜受体、细胞内信号蛋白的变化.结果与结论:音猬因子特异性膜受体Ptc、维甲酸特异性受体RARα、信号蛋白分子ptch1及Smad在正常细胞均有表达.经音猬因子诱导的细胞其Ptc表达上调,且随着诱导时间延长持续高表达,明显强于维甲酸诱导组及对照组(P < 0.01);其细胞内ptch1蛋白分子表达与此趋势一致,但不能引起RARα表达上调.经维甲酸刺激的细胞在诱导过程中没有激活Ptc通路,诱导4 d后RARα表达出现小幅上调并持续至6 d,但这一结果差异不具有显著性意义,ptch1的表达无明显变化.经音猬因子、维甲酸诱导的细胞Smad分子表达均上调,但无明显差异.证实音猬因子诱导方案通过持续激活其特异性受体途径参与细胞诱导分化过程,而维甲酸诱导方案和音猬因子诱导方案之间没有显著受体途径交叉.     

Establishment and characterization of a clonal human extraskeletal Ewing's sarcoma cell line, EES1

Ewing's sarcoma, a small round cell sarcoma arising in soft tissue as well as the bone, is one of the most malignant tumors in children and young adults. Few established cell lines of extraskeletal Ewing's sarcoma (EES) have been reported, which made it difficult to examine the biological features of EES. Therefore, we have established a new clonal cell line of EES. We report its morphological characters, results of chromosomal and immunohistochemical analysis. A piece of tumor obtained from the 18-year-old female patient with EES was xenografted in a nude mouse. In vitro subcultured cells were then obtained from this xenograft. A clonal cell line was subsequently established by limiting dilution and designated EES1. EES1 cells had a doubling time of 24 hours. In the xenografted tumor, the cells expressed vimentin, CD99 (MIC2), neuron specific enolase (NSE) and cytokeratin. The original tumor cells also expressed vimentin, CD 99, and NSE, but was negative for cytokeratin. The morphological and immunohistochemical features of this cell line established, except for cytokeratin expression, were consistent with those of the primary tumor. Cytogenetic analysis of EES1 revealed chromosomal translocation of t(11; 12)(q24;ql2). The chimeric fusion of the Ewing's sarcoma gene in band 22q12 with the Friend leukemia virus integration-1 gene in band 11q24 was also demonstrated. Fluorescence in situ hybridization further confirmed the presence of translocation involving the Ewing's sarcoma gene in both the primary tumor and EES1 cells. In conclusion, we have established a human EES cell line EES1, which will provide a useful model for studying various aspects of human EES.