胶质瘤细胞系SHG44中肿瘤干细胞存在的可能性

目的:探讨人类胶质瘤细胞系SHG44中干细胞存在的可能性。方法:应用N2无血清培养基进行培养,碱性成纤维细胞生长因子和表皮生长因子刺激细胞扩增,观察其增殖生长情况;应用免疫组织化学染色对培养的细胞及其分化的细胞进行鉴定。结果:胶质瘤细胞系SHG44在无血清的培养条件下细胞的形态发生改变,部分细胞聚集成类似神经干细胞的神经球,呈悬浮状态生长。免疫组织化学检查,细胞表达巢蛋白、波形蛋白和CD117这三种神经干细胞的标志物;分化后部分细胞表达神经元的标志物βⅢ型管蛋白、NF200、NSE和TrkC;大部分细胞表达星形胶质细胞的标志物胶质纤维酸性蛋白。结论:体外培养条件下,细胞表达神经干细胞的标志物,分化后同时表达神经元和星形胶质细胞表型,具有干细胞的性质。     

直接和间接共培养条件下人脐带间充质干细胞对恶性胶质瘤细胞系SHG44生长的抑制作用

背景:SHG44是一种恶性胶质瘤细胞系,其生物学性状稳定、易于培养,广泛应用于动物成瘤模型制作,目前对其研究主要集中在运用药物、基因转染及电离辐射等途径抑制其生长,未见间充质干细胞对其作用的相关报道。目的:通过直接和间接共培养的方法,探讨人脐带间充质干细胞对恶性胶质瘤细胞系SHG44的作用,观察SHG44胶质瘤细胞数量及细胞周期的变化。方法:将人脐带间充质干细胞与SHG44细胞,分别在24孔板进行直接共培养,在Transwell板进行间接共培养,分别设对照组。培养3d后在荧光显微镜下观察,并收集Transwell板中的SHG44胶质瘤细胞,应用流式细胞术分别检测SHG44细胞周期。结果与结论:直接接触共培养组SHG44胶质瘤细胞数量少于对照组(P<0.05)。Transwell间接接触共培养组SHG44胶质瘤细胞数量与对照组相比,差异无显著性意义(P>0.05),其细胞周期位于G0/G1期的SHG44胶质瘤细胞比率高于对照组(P<0.05)。证实,体外培养的人脐带间充质干细胞可以通过直接及间接接触抑制恶性胶质瘤细胞系SHG44细胞的生长。     

神经干细胞与脑胶质瘤干细胞

所有的肿瘤组织并不是由均一的肿瘤细胞所组成的,不同的细胞具有不同的增殖、浸润和转移能力,亦即肿瘤的异质性.其中存在少数担当着干细胞角色的肿瘤细胞,具有干细胞的基本特性,包括自我更新能力、无限的增殖能力和多向分化潜能,为肿瘤干细胞.神经干细胞具有很强的自我更新机制,获得较少突变即有可能恶性转化,而且干细胞存活时间较长,这意味着干细胞比成熟细胞发生细胞复制的错误几率更大.因外界环境的刺激而发生突变的机会更多,最终形成脑胶质瘤干细胞,同时调节神经干细胞增殖和自我更新的基因在脑胶质瘤的脑胶质瘤干细胞中也表达,这也是支持神经干细胞是脑胶质瘤干细胞来源的;也有推测认为它可能起源于已分化的细胞,由这些细胞突变发生去分化得来,并通过基因突变而获得了干细胞自我更新的特性,从而形成脑胶质瘤干细胞.通过探讨神经干细胞与脑胶质瘤干细胞,为脑胶质瘤的治疗提供依据.     

氯化甲基汞对人SHG44胶质瘤细胞抗肿瘤活性的体外实验研究

目的探讨氯化甲基汞(MMC)对人SHG44胶质瘤细胞株的增殖、杀伤和细胞凋亡的影响,为胶质瘤治疗提供理论依据。方法体外培养SHG44胶质瘤细胞,分为空白对照组和MMC实验组(按氯化甲基汞浓度分组)。采用MTT比色法检测不同浓度MMC对体外培养SHG44细胞的增殖抑制和杀伤作用。用流式细胞仪测定MMC对SHG44细胞凋亡/坏死的影响。结果在体外1.25、2.50、5.00和10.00μmol.L-1的MMC均可抑制SHG44胶质瘤细胞的增殖,SHG44胶质瘤细胞存活率明显低于对照组(P0.05),增殖抑制作用随浓度的增加而增强。SHG44胶质瘤细胞接触2.50、5.00和10.00μmol.L-1的MMC后4、8、16和32 h的细胞存活率明显低于对照组(P0.05),细胞杀伤作用随浓度的增加和时间的延长而增强。SHG44胶质瘤细胞接触0.075、0.15、0.3和1.2μmol.L-1氯化甲基汞12 h后细胞凋亡/坏死率呈现剂量依赖性增高趋势(P0.01)。结论MMC具有杀伤SHG44胶质瘤细胞、抑制其增殖、诱导凋亡的抗肿瘤活性,有应用于胶质瘤治疗的潜在价值。     

人脑胶质瘤中肿瘤干细胞的体外培养及生物学特性

背景:有研究者提出,脑内存在少量正常的神经干细胞能够向肿瘤组织迁移。这需要对从胶质瘤体外培养得到的肿瘤干细胞与正常的神经干细胞进行鉴别。目的:从人脑胶质瘤组织中分离脑胶质瘤干细胞进行体外培养,并对其干细胞特性加以鉴定,观察脑肿瘤干细胞的生长特性。设计、时间及地点:细胞学观察实验,于2007-02/12在解放军第四军医大学细胞工程研究中心完成。材料:7份肿瘤标本来源于胶质瘤患者,间变性星形细胞瘤标本3份,多形性胶质母细胞瘤标本4份。方法:将获取的胶质瘤细胞置于含2?7、表皮细胞生长因子、碱性成纤维细胞生长因子、左旋谷胺酰氨、胰岛素、青霉素和链霉素生长因子的无血清DMEM/F12培养基中,重新悬浮为单细胞悬液,以1×108L-1接种于含有B27、表皮细胞生长因子及碱性成纤维细胞生长因子的DMEM/F12培养基中培养分离培养肿瘤干细胞球。取第5代的肿瘤干细胞球,离心后除去原培养基,用含有体积分数为0.10胎牛血清的DMEM/F12培养基接种于放置有多聚赖氨酸包被盖玻片的小平皿中,观察肿瘤干细胞分化情况。主要观察指标:利用细胞免疫荧光及组织免疫组织化学法检测脑肿瘤干细胞在细胞培养或组织切片中CD133及巢蛋白表达。结果:在胶质瘤中存在一定量的细胞能在无血清培养基中存活并悬浮生长,并增殖形成克隆性脑肿瘤干细胞球,细胞核较大,核质比例高,具有肿瘤细胞的特性,与原肿瘤组织标本的苏木精-伊红染色比较,肿瘤干细胞分化后的子代细胞中大部分与胶质瘤细胞相似。原代及传代脑肿瘤干细胞表达神经干细胞的特异性标志物巢蛋白和CD133。结论:人脑胶质瘤中存在一定量的肿瘤干细胞,并能在体外将其分离培养,能够自我更新增殖、诱导分化,表达神经干细胞标志物CD133。     

神经干细胞在基因治疗胶质瘤中的研究进展

神经干细胞是近几年的研究热点之一,其作为基因治疗的载体更是引起了广泛的关注和深刻研究。本文就神经干细胞在基因治疗胶质瘤方面的优点、缺点,研究现状和发展方向做一综述。     

脑干胶质瘤的干细胞研究进展

脑十胶质瘤是威胁人类健康的重要疾病，尤其是弥漫内生性桥脑胶质瘤，对儿童的影响更是致命性的。脑干胶质瘤占儿童后颅窝肿瘤的30％，而弥漫内生性桥脑胶质瘤占儿童脑肿瘤15％左右。后者其中位生存时间几乎不超过1年。由于过去在其生物学特性等方面研究欠缺导致此类肿瘤的治疗几乎无实质性进展。但随着近年脑于胶质瘤干细胞及其相关信号通路、细胞因子等方面的基础研究兴起，治疗方面取得了一定的成绩。在此，我们将就近几年在弥漫内生性桥脑胶质瘤基础方面的研究进展作相关综述及讨论。     

神经干细胞和肿瘤干细胞在胶质瘤病因研究中的进展

胶质瘤是临床上最常见的中枢神经系统恶性肿瘤,约占颅内肿瘤的一半左右。其侵袭性强,并具有由低级别向高级别转化的生物学特点。胶质瘤确切的发病原因目前尚未明确,一般认为与环境、遗传及机体免疫功能失调等综合因素有关。其中,有关神经干细胞（neural stem cell,NSC）、胶质瘤肿瘤干细胞和正常胶质细胞的关系问题是目前胶质瘤病因研究的热点方向。现就有关研究综述如下。     

丙戊酸钠对人脑胶质瘤细胞系SHG-44的放疗增敏作用

目的:研究丙戊酸钠对人脑胶质瘤细胞系SHG-44的放疗增敏作用及其可能机制.方法:应用0.5、1.0、2.0、4.0、8.0 mmol/L丙戊酸钠干预体外培养的SHG-44细胞,MTT法检测不同时间及不同剂量丙戊酸钠对SHG-44细胞的抑制率、以克隆形成率实验检测丙戊酸钠对SHG-44细胞的放射增敏比、流式细胞术检测细胞凋亡及周期差异.结果:丙戊酸钠明显抑制细胞增殖,并具有时间及剂量依赖性,并且对胶质瘤细胞株SHG-44具有放疗增敏作用,放射增敏比为1.32;流式细胞术分析见细胞凋亡,联合组较对照组明显增加,细胞周期中联合组G0/G1期细胞比例升高,S期细胞比例降低,联合组与各单独作用组相比差异显著.结论:丙戊酸钠能增强SHG-44细胞放疗敏感性,其作用可能是通过诱导细胞凋亡、改变细胞周期时相分布等机制来实现的.     

人胶质瘤细胞系CHG-5和SHG-44差异表达基因的鉴定

目的：采用基因芯片技术分析不同恶性程度胶质瘤细胞CHG-5（WHO分级为级）和SHG-44（WHO分级为级）的差异表达基因。方法：抽提总RNA,进行RT-PCR,并用荧光染料Cy3和Cy5标记cDNA产物,然后进行芯片杂交,检测CHG-5和SHG-44基因表达的差异,并用Northern blot杂交来验证芯片结果。结果：与CHG-5相比,SHG-44细胞中检测到有103个基因表达明显上调,89个表达明显下调。芯片结果得到Northern blot杂交结果的支持。结论：初步揭示了胶质瘤进展的差异表达基因,为胶质瘤的进一步研究提供了基础资料。     

人脐带源神经干细胞的培养和分化

目的研究诱导人脐带间充质干细胞(hucMSC)分化为神经干细胞样细胞(hucNSC)的方法。方法体外培养hucMSC,流式细胞仪鉴定细胞表型的表达。用碱性成纤维细胞生长因子、表皮生长因子添加B27诱导,流式细胞学、免疫细胞化学鉴定。用胶质源性神经营养因子(GDNF)、白介素-1β(IL-1β)和全反式维甲酸(ATRA)等诱导分化,免疫组化染色、RT-PCR鉴定。结果hucMSC表达CD105、CD44、CD29。诱导后聚集成细胞球悬浮生长,并不断增殖,流式细胞仪鉴定失去hucMSC的表面标志物特征,而表达Nestin、CD133。再经RA、GDNF、IL-1β诱导,细胞表达胶质纤维酸性蛋白、神经元特异性烯醇化酶和酪氨酸羟化酶。结论hucMSC能分化为具有神经干细胞样生长、增殖、分化特征的细胞。     

Primary Bioassay of Human Myeloma Stem Cells

The ability to clone primary tumors in soft agar has proven useful in the study of the kinetics and biological properties of tumor stem cells. We report the development of an in vitro assay which permits formation of colonies of human monoclonal plasma cells in soft agar. Colony growth has been observed from bone marrow aspirates from 75% of the 70 patients with multiple myeloma or related monoclonal disorders studied. Growth was induced with either 0.02 ml of human type O erythrocytes or 0.25 ml of medium conditioned by the adherent spleen cells of mineral oil-primed BALB/c mice. 5-500 colonies appeared after 2-3 wk in culture yielding a plating efficiency of 0.001-0.1%. The number of myeloma colonies was proportional to the number of cells plated between concentrations of 10(5)-10(6) and back-extrapolated through zero, suggesting that colonies were clones derived from single myeloma stem cells. Morphological, histochemical, and functional criteria showed the colonies to consist of immature plasmablasts and mature plasma cells. 60-80% of cells picked from colonies contained intracytoplasmic monoclonal immunoglobulin. Colony growth was most easily achieved from the bone marrow cells of untreated patients or those in relapse. Only 50% of bone marrow samples from patients in remission were successfully cultured. Tritiated thymidine suicide studies provided evidence that for most myeloma patients, a very high proportion of myeloma colony-forming cells was actively in transit through the cell cycle. Velocity sedimentation at 1 g showed myeloma stem cells sedimented in a broad band with a peak at 13 mm/h. Antibody to granulocyte colony-stimulating factor did not reduce the number or size of the colonies. Increased numbers of myeloma colonies were seen when the marrow was depleted of colony-stimulating factor elaborating adherent cells before plating. This bioassay should prove useful in studying the in vitro biological behavior of certain bone marrow-derived (B)-cell neoplasia. In addition, systematic and predictive studies of anticancer drug effects on myeloma stem cells should now be feasible.     

Can Mesenchymal Stem Cells Induce Tolerance to Cotransplanted Human Embryonic Stem Cells?

Mesenchymal stem cells (MSCs) are reported to be immune privileged. We assessed whether their transplantation (Tx) could create a suppressive microenvironment mitigating rejection of coinjected human embryonic stem cells (hESCs). Three weeks after ligation-induced myocardial infarction, 40 immunocompetent rats received 150 µl of cardiac-specified hESCs (5 × 10⁶), MSCs (5 × 10⁶), hESC + MSC (5 × 10⁶ for each), or control medium. Two months after Tx, left ventricle (LV) function was assessed by echocardiography, and hearts were processed for the detection of human cells by immunostaining and quantitative RT-PCR, patterns of rejection, fibrosis, and angiogenesis. Two months after Tx, LV ejection fraction (LVEF) was significantly higher in the ESC and ESC + MSC groups compared with controls. There were few engrafted cells, which expressed markers of endothelial, smooth muscle, and ventricular cardiac cells, particularly in the MSC group. Hearts of all groups demonstrated a similar infiltration by CD4⁺ and CD3⁺ cells but MSC-Tx resulted in a greater infiltration of FoxP3 compared with the control and ESC-alone groups. No teratoma was observed. Thus, cotransplantation of ESCs and MSCs provided better functional preservation compared with single-cell treatment alone. However, there was only modest evidence for an immunosuppressive effect of coinjected MSCs and their beneficial effects seemed rather mediated by trophic effects on the host tissue.     

HLA Engineering of Human Pluripotent Stem Cells

The clinical use of human pluripotent stem cells and their derivatives is limited by the rejection of transplanted cells due to differences in their human leukocyte antigen (HLA) genes. This has led to the proposed use of histocompatible, patient-specific stem cells; however, the preparation of many different stem cell lines for clinical use is a daunting task. Here, we develop two distinct genetic engineering approaches that address this problem. First, we use a combination of gene targeting and mitotic recombination to derive HLA-homozygous embryonic stem cell (ESC) subclones from an HLA-heterozygous parental line. A small bank of HLA-homozygous stem cells with common haplotypes would match a significant proportion of the population. Second, we derive HLA class I–negative cells by targeted disruption of both alleles of the Beta-2 Microglobulin (B2M) gene in ESCs. Mixed leukocyte reactions and peptide-specific HLA-restricted CD8⁺ T cell responses were reduced in class I–negative cells that had undergone differentiation in embryoid bodies. These B2M^−/− ESCs could act as universal donor cells in applications where the transplanted cells do not express HLA class II genes. Both approaches used adeno-associated virus (AAV) vectors for efficient gene targeting in the absence of potentially genotoxic nucleases, and produced pluripotent, transgene-free cell lines.