乳腺癌肿瘤干细胞的研究进展

干细胞(stem cell,SC)是一类具有自我更新、多向分化潜能的特殊细胞群体.而肿瘤干细胞(cancer stem cell,CSC)不仅具备了干细胞方面的特征,同时还有其自身特殊性.乳腺癌中肿瘤干细胞的发现为乳腺癌的治疗提供了创新性策略.近年来,有关乳腺癌肿瘤干细胞的筛选标记和方法以及信号转导通路方面的研究颇多,但其中也不乏争议.就乳腺癌干细胞研究的最新进展作一端述.     

乳腺癌干细胞和乳腺癌

肿瘤干细胞既包含干细胞的特性也包含肿瘤细胞的特性。乳腺癌起源于乳腺癌干细胞的说法能够合理地解释乳腺癌的不均一性及其治疗后的复发,这些变异的干细胞可能作为肿瘤预防策略的靶标。而且,由于乳腺癌干细胞能够抵抗辐射治疗和化学治疗,所以要想更好地治疗乳腺癌就需要寻找针对这些干细胞的靶标。我们综述了乳腺癌干细胞的发现、富集和分离、相关的信号途径,以及在乳腺癌治疗中的应用。     

CD44+CD24-Λow乳腺癌干细胞的流式分选及其肿瘤干细胞特性的初步鉴定

目的:通过表面标志分选法富集乳腺癌干细胞,并初步鉴定其肿瘤干细胞特性.方法:采用流式细胞分选术从人乳腺癌细胞系MCF-7中分选CD44+CD24-Λow乳腺癌干细胞,并进行干细胞比例分析;用免疫荧光法检测、比较分选获得的细胞和对照细胞的干性和分化标记物Oct-4、SOX-2、CK-18和α-SMA的表达状态.结果:分选获得的CD44+CD24-Λow乳腺癌干细胞阳性比例达90％以上;免疫荧光检测结果显示,CD44+CD24-Λow细胞亚群比non-CD44+CD24-Λow细胞亚群高表达干细胞转录因子Oct-4、SOX-2,低表达分化因子CK-18、α-SMA;体外实验表明,CD44+CD24-Λow细胞亚群具有更强的成球生长能力,并具有双向分化潜能.结论:CD44+CD24-Λow表面标记物分选的方法可以富集高纯度的乳腺癌干细胞,且呈现干性因子Oct-4和SOX-2高表达.     

肿瘤干细胞起源及其生物学特性

肿瘤干细胞与正常成体干细胞在自我更新与增殖分化能力、表型标记和强耐药性等诸多方面存在着相类似的生物学特征,所以肿瘤干细胞被推测为肿瘤发生的细胞起源。基于肿瘤干细胞与正常干细胞之间的相似性质和肿瘤发生的分子机制,科学家建立了一系列从肿瘤组织或肿瘤细胞系分离肿瘤干细胞的实验方法和研究肿瘤干细胞起源的动物实验模型。现就目前在肿瘤干细胞起源和生物学特性领域的研究作概括阐述。     

CD44+CD24-/low乳腺癌干细胞的流式分选及其肿瘤干细胞特性的初步鉴定

目的:通过表面标志分选法富集乳腺癌干细胞,并初步鉴定其肿瘤干细胞特性。方法:采用流式细胞分选术从人乳腺癌细胞系MCF-7中分选CD44+CD24-/low乳腺癌干细胞,并进行干细胞比例分析;用免疫荧光法检测、比较分选获得的细胞和对照细胞的干性和分化标记物Oct-4、SOX-2、CK-18和α-SMA的表达状态。结果:分选获得的CD44+CD24-/low乳腺癌干细胞阳性比例达90%以上;免疫荧光检测结果显示,CD44+CD24-/low细胞亚群比non-CD44+CD24-/low细胞亚群高表达干细胞转录因子Oct-4、SOX-2,低表达分化因子CK-18、α-SMA;体外实验表明,CD44+CD24-/low细胞亚群具有更强的成球生长能力,并具有双向分化潜能。结论:CD44+CD24-/low表面标记物分选的方法可以富集高纯度的乳腺癌干细胞,且呈现干性因子Oct-4和SOX-2高表达。     

结肠癌肿瘤干细胞的研究进展

肿瘤干细胞(cancer stem cell,CSC)是一小群能够自我复制和分化的细胞,它既具有干细胞的特征,又有自身独有的特点。结肠癌中肿瘤干细胞的发现为治愈结肠癌提供了新的治疗策略。目前关于结肠癌中肿瘤干细胞的分选标记和分子细胞学特性研究较多,但仍然存在较多争议。     

乳腺癌干细胞的研究进展

乳腺癌是女性最常见恶性肿瘤.随着乳腺癌发生、发展研究的不断深入,乳腺癌干细胞日益受到研究者们的重视.乳腺癌干细胞是首次分离出来的实体干细胞,研究表明,它是一群未分化、具有多种分化和自我更新能力的细胞.正常情况下,乳腺干细胞的分化、更新能力受激素及信号转导通路的严格控制,一旦这种机制被破坏或发生异常,干细胞就会异常分化,变成乳腺癌干细胞,并无限生长形成肿瘤.乳腺癌干细胞具有放、化疗抵抗性,高致瘤性及高侵袭转移性,其在乳腺癌的发生、发展及复发、转移过程起到非常重要的作用.因而,要想更好地治疗乳腺癌就需要寻找针对这些干细胞的靶标,从而为临床靶向治疗乳腺癌提供依据.本文对乳腺癌干细胞在乳腺癌研究及治疗中的最新进展进行综述.     

干细胞用于乳腺癌治疗的研究进展

乳腺癌是女性最常见的恶性肿瘤之一,是一种严重影响女性身心健康甚至危及生命的恶性肿瘤,男性乳腺癌罕见.目前,乳腺癌的治疗仍以外科治疗为主.随着干细胞生物学的发展,人们发现造血干细胞移植在恶性肿瘤大剂量放、化疗后的造血重建和免疫重建中有着重要作用,而间充质干细胞可以作为基因栽体而抑制肿瘤细胞的生长.这些研究为乳腺癌的治疗提供了全新的思路.分析目前人们应用干细胞治疗乳腺癌的研究现状,同时统计分析了中国临床试验注册中心数据库和美国clinicaltrials 数据库中用干细胞治疗乳腺癌的临床试验的最新数据,并且指出了干细胞用于乳腺癌治疗的研究趋势,目的是为后续开展的用干细胞治疗乳腺癌的研究提供一定的参考.     

乳腺癌干细胞调控及靶向治疗研究进展

乳腺癌干细胞是乳腺肿瘤内具有自我更新能力以及多向分化潜能的细胞,乳腺癌的发生﹑发展、转移﹑复发与干细胞的高致瘤性、高侵袭转移性、治疗抵抗能力密切相关。深入研究乳腺癌干细胞相关细胞因子及微环境因素的调控对乳腺癌的临床靶向治疗具有重要指导意义。该文就近年来乳腺癌干细胞调控相关信号转导通路、转录因子、表观遗传调控因子以及微环境因素进行综述,探讨乳腺癌干细胞及其相关信号因子作为乳腺癌治疗靶点的潜在价值,为临床靶向治疗乳腺癌提供新方向。     

乳腺癌干细胞研究进展

乳腺癌在女性肿瘤相关性疾病的死亡中占有主要地位,乳腺癌干细胞在乳腺癌的发生、发展、治疗抵抗性、转移及复发中起到了关键作用。鉴于乳腺癌干细胞对治疗乳腺癌的重要意义,我们就乳腺癌干细胞的发现、研究意义、研究现状及研究中存在的问题做简要综述,以期为乳腺癌的研究开拓新的思路。     

Identification of single chain antibodies to breast cancer stem cells using phage display

Recent evidence suggests that most malignancies are driven by “cancer stem cells” sharing the signature characteristics of adult stem cells: the ability to self renew and to differentiate. Furthermore these cells are thought to be quiescent, infrequently dividing cells with a natural resistance to chemotherapeutic agents. These studies theorize that therapies, which effectively treat the majority of tumor cells but ‘miss’ the stem cell population, will fail, while therapies directed at stern cells can potentially eradicate tumors. In breast cancer, researchers have isolated ‘breast cancer stem cells’ capable of recreating the tumor in vivo and in vitro. Generated new tumors contained both additional numbers of cancer stem cells and diverse mixed populations of cells present in the initial tumor, supporting the intriguing self‐renewal and differentiation characteristics. In the present study, an antibody phage library has been used to search for phage displayed‐single chain antibodies (scFv) with selective affinity to specific targets on breast cancer stem cells. We demonstrate evidence of two clones binding specifically to a cancer stem cell population isolated from the SUMl59 breast cancer cell line. These clones had selective affinity for cancer stem cells and they were able to select cancer stem cells among a large population of non‐stem cancer cells in paraffin‐embedded sections. The applicability of these clones to paraffin sections and frozen tissue specimens made them good candidates to be used as diagnostic and prognostic markers in breast cancer patient samples taking into consideration the cancer stern cell concept in tumor biology. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

MicroRNAs and breast cancer stem cells: Potential role in breast cancer therapy

MicroRNAs (miRNAs) can control cancer and cancer stem cells (CSCs), and this topic has drawn immense attention recently. Stem cells are a tiny population of a bulk of tumor cells that have enormous potential in expansion and metastasis of the tumor. miRNA have a crucial role in the management of the function of stem cells. This role is to either promote or suppress the tumor. In this review, we investigated the function and different characteristics of CSCs and function of the miRNAs that are related to them. We also demonstrated the role and efficacy of these miRNAs in breast cancer and breast cancer stem cells (BCSC). Eventually, we revealed the metastasis, tumor formation, and their role in the apoptosis process. Also, the therapeutic potential of miRNA as an effective method for the treatment of BCSC was described. Extensive research is required to investigate the employment or suppression of these miRNAs for therapeutics approached in different cancers in the future.     

Cancer stem cells in glioblastoma — molecular signaling and therapeutic targeting

Glioblastomas (GBMs) are highly lethal primary brain tumors. Despite current therapeutic advances in other solid cancers, the treatment of these malignant gliomas remains essentially palliative. GBMs are extremely resistant to conventional radiation and chemotherapies. We and others have demonstrated that a highly tumorigenic subpopulation of cancer cells called GBM stem cells (GSCs) promotes therapeutic resistance. We also found that GSCs stimulate tumor angiogenesis by expressing elevated levels of VEGF and contribute to tumor growth, which has been translated into a useful therapeutic strategy in the treatment of recurrent or progressive GBMs. Furthermore, stem cell-like cancer cells (cancer stem cells) have been shown to promote metastasis. Although GBMs rarely metastasize beyond the central nervous system, these highly infiltrative cancers often invade into normal brain tissues preventing surgical resection, and GSCs display an aggressive invasive phenotype. These studies suggest that targeting GSCs may effectively reduce tumor recurrence and significantly improve GBM treatment. Recent studies indicate that cancer stem cells share core signaling pathways with normal somatic or embryonic stem cells, but also display critical distinctions that provide important clues into useful therapeutic targets. In this review, we summarize the current understanding and advances in glioma stem cell research, and discuss potential targeting strategies for future development of anti-GSC therapies.     

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。     

癌干细胞研究进展

关于肿瘤发生及发展的机制人们已探索多年,但由于肿瘤病因本身的复杂性、研究技术和知识积累不足等各种原因,研究进展缓慢。近些年来,癌干细胞的发现、确认和特性研究为肿瘤发病机制的揭示,乃至新型高效治疗策略的制定提出了新线索。许多研究成果显示,癌干细胞因具有自我更新和潜在的强增殖能力,在肿瘤发生发展、复发转移中均发挥着很重要的作用;肿瘤化疗的失败与肿瘤组织中癌干细胞的耐药性可能存在密切关系。本文就癌干细胞在这方面的研究进展及存在的问题作一综述。     

Human umbilical cord mesenchymal stem cells suppress breast cancer tumourigenesis through direct cell-cell contact and internalization

The purpose of this study was to investigate how human umbilical cord mesenchymal stem cells (HUMSCs) affect breast cancer tumourigenesis. To observe the influence of HUMSCs on tumourigenesis in vitro, we performed a co-culture of MDA MB-231 breast cancer cells with HUMSCs, and a result of HUMSCs on tumourigenesis in vivo was achieved by injection of HUMSCs into nonobese diabetic/severe combined immunodeficient mice following tumour establishment with MDA-MB231. During the co-culture, apoptosis of MDA-MB231 was noted, which was driven either by binding with HUMSC through direct cell-cell contact or by formation of a novel cell-in-cell phenomenon after internalization of HUMSC. Also, treatment with HUMSC injection was efficacious in both in situ and metastatic breast cancers in the animal models. Since HUMSCs were proved to efficaciously suppress breast cancer tumourigenesis both in vitro and in vivo, it is our expectation that treatment with HUMSCs can be a viable therapy for breast cancer in the near future. In addition, we share a new point of view on the role of HUMSCs in foetal development during pregnancy.     

Discovering alkylamide derivatives of bexarotene as new therapeutic agents against triple-negative breast cancer

Triple-negative breast cancer (TNBC) has been reported to be correlated with high expression of proliferation markers as well as constitutive activation of metastasis-relevant signaling pathways. For many years, breast cancer researchers have been investigating specific and effective methods to treat or to control the development of TNBC, but promising therapeutic options remain elusive. In this study, we have demonstrated that alkylamide derivatives of bexarotene DK-1–150 and DK-1–166 induce apoptotic cell death in TNBC cell lines without causing cytotoxicity in the normal mammary epithelial cell line. Furthermore, the bexarotene derivatives also showed significant effects in inhibiting TNBC cell proliferation and migration, modulating cancer stem cell markers expressions, as well as limiting the epithelial-mesenchymal transition (EMT) activities of TNBC cell lines in terms of downregulating EMT marker and blocking nuclear translocation of β-catenin. Therefore, we propose the alkylamide derivatives of bexarotene as potential candidates for novel anticancer therapeutics against TNBC.     

Mesenchymal traits are selected along with stem features in breast cancer cells grown as mammospheres

Increasing evidence indicates that invasive properties of breast cancers rely on gain of mesenchymal and stem features, which has suggested that the dual targeting of these phenotypes may represent an appealing therapeutic strategy. It is known that the fraction of stem cells can be enriched by culturing breast cancer cells as mammospheres (MS), but whether these pro-stem conditions favor also the expansion of cells provided of mesenchymal features is still undefined. In the attempt to shed light on this issue, we compared the phenotypes of a panel of 10 breast cancer cell lines representative of distinct subtypes (luminal, HER2-positive, basal-like and claudin-low), grown in adherent conditions and as mammospheres. Under MS-proficient conditions, the increment in the fraction of stem-like cells was associated to upregulation of the mesenchymal marker Vimentin and downregulation of the epithelial markers expressed by luminal cells (E-cadherin, KRT18, KRT19, ESR1). Luminal cells tended also to upregulate the myoepithelial marker CD10. Taken together, our data indicate that MS-proficient conditions do favor mesenchymal/myoepithelial features, and indicate that the use of mammospheres as an in vitro tumor model may efficiently allow the exploitation of therapeutic approaches aimed at targeting aggressive tumors that have undergone epithelial-to-mesenchymal transition.