肿瘤转移干细胞与抗转移策略

肿瘤干细胞（cancer stem cell,CSC）能自我更新,分化形成异质性的肿瘤子代细胞群,是肿瘤复发与转移的主要原因。肿瘤转移干细胞（metastatic cancer stem cell,MCSC）具有CSC特性,同时伴有转移能力。肿瘤转移既发生于肿瘤晚期,也发生于早期。MCSC在起源、上皮-间质转变（epithelial-mesenchymal transition,EMT）、间质-上皮转变（mesenchymal-epithelial transition,MET）和靶器官小生境（niche）等方面与CSC不同,因而MCSC是肿瘤转移的基础。杀灭CSC、阻断EMT和MET、抑制MCSC微血管黏附和阻断MCSC依赖的小生境可构建抗肿瘤转移的治疗策略。本文主要介绍MCSC的可能来源,MCSC的生物学特性,MCSC近期研究中可能取得的突破,以及针对MCSC的抗转移策略,为肿瘤转移机制研究和抗转移研究提供参考。     

小白菊内酯体内杀伤小鼠乳腺癌肿瘤干细胞

目的： 探讨小白菊内酯（parthenolide,PTL）对小鼠乳腺癌肿瘤干细胞（cancer stem cell,CSC）的杀伤作用,为临床应用PTL治疗乳腺癌提供实验依据。 方法： 采用5-氟尿嘧啶（5-fluorouracil, 5-FU）化疗法制备富含CSC的小鼠4T1细胞乳腺癌模型,随机分为对照组、5-FU组、PTL组。4周后脱颈处死小鼠,检测各组小鼠肿瘤的体积和重量,流式细胞术检测小鼠肿瘤组织中CD44+CD24-/low细胞比例,Hoechst33342染色法检测侧群（side population,SP）细胞的比例,免疫组化法检测CD55和乙醛脱氢酶1（aldehyde dehydrogenase1,ALDH1）蛋白的表达,倒置显微镜观察乳腺癌细胞微球体的形成。 结果： 成功制备富含CSC的小鼠乳腺癌细胞移植瘤模型,PTL可下调小鼠肿瘤组织中CD44+CD24-/low细胞的比例\[（42.5±3.7）% vs （68.7±32）%,P<0.05\],有效降低荷瘤小鼠肿瘤组织中SP细胞的比例\[（39.2±1.8）% vs （61.3±2.6）%,P<0.05\],下调小鼠移植瘤组织中CD55和ALDH1蛋白的表达\[（18.9±1.5）% vs （30.1±1.3）%,（8.1±2.3）% vs （18.0±1.4）%;均P<0.05\],抑制小鼠肿瘤细胞在无血清培养条件下形成微球体,并可抑制小鼠移植瘤的体积和重量\[（0.625±0.159）cm3 vs （1.715±0184）cm3,（1.467±0.373）g vs （3.367±0.398）g;均P<0.05\]。 结论： PTL在荷瘤小鼠体内可以明显降低肿瘤组织CSC含量,提示PTL可用来靶向杀伤乳腺癌CSC。     

HPV16 increases the number of migratory cancer stem cells and modulates their miRNA expression profile in oropharyngeal cancer

Human papillomavirus type 16 (HPV16) is a major risk for development of oropharyngeal squamous‐cell‐carcinoma (OPSCC). Although HPV⁺ OPSCC metastasize faster than HPV^? tumors, they have a better prognosis. The molecular and cellular alterations underlying this pathobiology of HPV⁺ OPSCC remain elusive. In this study, we examined whether expression of HPV16‐E6E7 targets the number of migratory and stationary cancer stem cells (CSC). Furthermore, we wanted to elucidate if aberrantly expressed miRNAs in migratory CSC may be responsible for progression of OPSCCs and whether they may serve as potential novel biomarkers for increased potential of metastasis. Our studies revealed that HPV16‐E6E7 expression leads to an increase in the number of stationary (CD44^high/EpCAM^high) stem cells in primary keratinocyte cultures. Most importantly, expression of E6E7 in the cell line H357 increased the migratory (CD44^high/EpCAM^low) CSC pool. This increase in migratory CSCs could also be confirmed in HPV⁺ OPSCC. Differentially expressed miRNAs from HPV16‐E6E7 positive CD44^high/EpCAM^low CSCs were validated by RT‐qPCR and in situ hybridization on HPV16⁺ OPSCCs. These experiments led to the identification of miR‐3194‐5p, which is upregulated in primary HPV16⁺ OPSCC and matched metastasis. MiR‐1281 was also found to be highly expressed in HPV⁺ and HPV^? metastasis. As inhibition of this miRNA led to a markedly reduction of CD44^high/EpCAM^low cells, it may prove to be a promising drug target. Taken together, our findings highlight the capability of HPV16 to modify the phenotype of infected stem cells and that miR‐1281 and miR3194‐5p may represent promising targets to block metastatic spread of OPSCC.     

肿瘤干细胞的研究进展

近年来随着对肿瘤研究的不断深入,以及对干细胞了解的日益加深,越来越多的证据显示肿瘤与干细胞有着密切的关系,肿瘤可能是干细胞在异常微环境中差异分化的结果,并提出了肿瘤干细胞（tumor stem cell,TSC）的学说。本文综述了肿瘤干细胞的发现、特点,以及在肿瘤的诊断、治疗和预后判断中的作用,旨在为肿瘤发生发展研究及干细胞在肿瘤治疗方面的应用提供理论依据。     

Evaluating the link between stem cells and breast cancer

Mammary stem cells have recently been identified and purified on the basis of surface antigens and transplantation assays. In addition, recent reports have identified a small sub-population of highly tumorigenic cells within primary and metastatic breast tumors and in a number of breast cancer cell lines. This suggests that, similarly to its normal physiological counterpart, a cancer stem cell may be at the origin of breast cancer. These observations have dramatic biological and clinical implications, as they dictate a revision of our understanding of breast cancer and of our therapeutic strategies. The aim of this article is to review recent data regarding normal mammary epithelial stem cells and evidence in support of the cancer stem cell hypothesis in the breast, and to provide further insight into how taking this subpopulation of cells into account may affect the way we treat epithelial cancers in the future.     

Cancer stem cells in human gastrointestinal cancer

Cancer stem cells (CSCs) are thought to be responsible for tumor initiation, drug and radiation resistance, invasive growth, metastasis, and tumor relapse, which are the main causes of cancer‐related deaths. Gastrointestinal cancers are the most common malignancies and still the most frequent cause of cancer‐related mortality worldwide. Because gastrointestinal CSCs are also thought to be resistant to conventional therapies, an effective and novel cancer treatment is imperative. The first reported CSCs in a gastrointestinal tumor were found in colorectal cancer in 2007. Subsequently, CSCs were reported in other gastrointestinal cancers, such as esophagus, stomach, liver, and pancreas. Specific phenotypes could be used to distinguish CSCs from non‐CSCs. For example, gastrointestinal CSCs express unique surface markers, exist in a side‐population fraction, show high aldehyde dehydrogenase‐1 activity, form tumorspheres when cultured in non‐adherent conditions, and demonstrate high tumorigenic potential in immunocompromised mice. The signal transduction pathways in gastrointestinal CSCs are similar to those involved in normal embryonic development. Moreover, CSCs are modified by the aberrant expression of several microRNAs. Thus, it is very difficult to target gastrointestinal CSCs. This review focuses on the current research on gastrointestinal CSCs and future strategies to abolish the gastrointestinal CSC phenotype.     

Normal stem cells in cancer prone epithelial tissues

The concept of a cancer stem cell is not a new one, being first suggested over 100 years ago. Over recent years the concept has enjoyed renewed enthusiasm, partly because of our growing understanding of the nature of somatic stem cells, but also because of a growing realisation that the development of strategies that target cancer stem cells may offer considerable advantages over conventional approaches. However, despite this renewed enthusiasm the existence of cancer stem cells remains controversial in many tumour types and any potential relationship to the normal stem cell pool remains poorly defined. This review summarises key elements of our understanding of the normal stem cell populations within animal models of the predominant cancer prone epithelial tissues, and further investigates the potential links between these populations and putative cancer stem cells.     

乳腺癌干细胞的研究进展

乳腺癌干细胞是一类具有自我更新能力、多向分化潜能和高度致瘤能力的细胞亚群,与乳腺癌的发生、发展、复发、转移以及治疗抵抗等密切相关。现就近年来乳腺癌干细胞的研究进展作一综述。     

Cell cycle heterogeneity and plasticity of colorectal cancer stem cells

Cancer stem cells (CSCs) are a long-lived and self-renewing cancer cell population that drives tumor propagation and maintains cancer heterogeneity. They are also implicated in the therapeutic resistance of various types of cancer. Recent studies of CSCs in colorectal cancer (CRC) have uncovered fundamental paradigms that have increased understanding of CSC systems in solid tumors. Colorectal CSCs share multiple biological properties with normal intestinal stem cells (ISCs), including expression of the stem cell marker Lgr5. New evidence suggests that colorectal CSCs manifest substantial heterogeneity, as exemplified by the existence of both actively cycling Lgr5⁺ CSCs as well as quiescent Lgr5⁺ CSCs that are resistant to conventional anticancer therapies. The classical view of a rigid cell hierarchy and irreversible cell differentiation trajectory in normal and neoplastic tissues is now challenged by the finding that differentiated cells have the capacity to revert to stem cells through dynamic physiological reprogramming events. Such plasticity of CSC systems likely underlies both carcinogenesis and therapeutic resistance in CRC. Further characterization of the mechanisms underpinning the heterogeneity and plasticity of CSCs should inform future development of eradicative therapeutic strategies for CRC.     

Therapeutic strategies targeting cancer stem cells

Increasing studies have demonstrated a small proportion of cancer stem cells (CSCs) exist in the cancer cell population. CSCs have powerful self-renewal capacity and tumor-initiating ability and are resistant to chemotherapy and radiation. Conventional anticancer therapies kill the rapidly proliferating bulk cancer cells but spare the relatively quiescent CSCs, which cause cancer recurrence. So it is necessary to develop therapeutic strategies acting specifically on CSCs. In recent years, studies have shown that therapeutic agents such as metformin, salinomycin, DECA-14, rapamycin, oncostatin M (OSM), some natural compounds, oncolytic viruses, microRNAs, cell signaling pathway inhibitors, TNF-related apoptosis inducing ligand (TRAIL), interferon (IFN), telomerase inhibitors, all-trans retinoic acid (ATRA) and monoclonal antibodies can suppress the self-renewal of CSCs in vitro and in vivo. A combination of these agents and conventional chemotherapy drugs can significantly inhibit tumor growth, metastasis and recurrence. These strategies targeting CSCs may bring new hopes to cancer therapy.     

肿瘤干细胞标志物与胃癌关系的研究进展

肿瘤干细胞（cancer stem cell,CSCs）是理论认为肿瘤中存在一小部分细胞具有自我更新和多向分化的潜能,具有特异性表面标志的细胞.目前已经从乳腺癌、结直肠癌、皮肤癌等多种恶性肿瘤中鉴定分离出了各自的肿瘤干细胞标志物.本文就与胃癌相关的干细胞标志物进行综述.     

肿瘤干细胞研究进展

目的:了解近年来肿瘤千细胞的研究进展.方法:应用检索Pubmed数据库检索系统,以"肿瘤"、"干细胞"、"肿瘤干细胞"为关键词,检索1979-01-2008-12的相关文献,共检索到英文文献2 760条.纳入标准:1)肿瘤干细胞的表面标志、耐药机制、信号传导通路;2)肿瘤干细胞来源;3)肿瘤干细胞与肿瘤临床诊治的联系.根据纳入标准,最后精选33篇文献进行分析综述.结果:肿瘤干细胞能够自我更新和分化,具有特异的表面分子标志,对放化疗不敏感.肿瘤干细胞存在Wnt、Notch、Hedgehog、Bmi-1等调节细胞自我更新信号通路异常.肿瘤干细胞是维持肿瘤生长、复发和转移的根源,已经成为抗肿瘤研究的靶细胞.结论:肿瘤干细胞研究进展迅速,深入研究肿瘤干细胞的特性,对恶性肿瘤的诊断,治疗和预后评估具有重要意义.肿瘤干细胞理论将改变目前肿瘤的诊治模式.     

TRAIL-expressing mesenchymal stem cells kill the putative cancer stem cell population

Background:

Tumours contain stem-like, side population (SP) cells, which have increased tumorigenic potential, resistance to traditional therapies and may be responsible for treatment failures and relapse in patients.

Methods:

Mesenchymal stem cells (MSCs) were engineered to express the apoptotic ligand, TNF-related apoptosis-inducing ligand (TRAIL). Squamous (H357) and lung (A549) cancer cell lines were sorted into side and non-side populations (non-SP) by Hoechst flow cytometry. The survival and growth of both SP and non-SP cancer populations, in conjunction with TRAIL-expressing MSCs and mitoxantrone chemotherapy, were assessed by flow cytometry and colony forming ability.

Results:

Mesenchymal stem cells expressing TRAIL migrate to tumours and reduce the growth of primary cancers and metastases. This report demonstrates that these cells cause apoptosis, death and reduced colony formation of the SP of squamous and adenocarcinoma lung cancer cells and are synergistic when combined with traditional chemotherapy in apoptosis induction.

Conclusions:

The sensitivity of putative cancer stem cells to TRAIL-expressing MSCs, suggests their possible role in the prevention of cancer relapse.     

以肿瘤干细胞为靶的免疫治疗

肿瘤干细胞(cancer stem cell,CSC)是肿瘤发生和转移的种子细胞,CSC具有自我更新、增殖和不完全分化的能力。CSC对化疗/放疗的抵抗以及免疫逃逸成为肿瘤复发的根源,要提高肿瘤治愈率必须彻底清除CSC。认识CSC的标记特征和"干性"调节关键分子才能有效和特异地攻击CSC。免疫治疗具有抗原识别的靶向性和时空效应性,是以CSC为靶的治疗的基础;以单克隆抗体和致敏的免疫细胞为主要治疗技术的免疫治疗清除CSC具有可实践性和挑战性。     

间充质干细胞源性外泌体及其在肿瘤治疗中的研究进展

外泌体（exosomes）是细胞内多囊泡体（multivesicular bodies,MVBs）与细胞膜融合后释放到细胞外直径为40~100nm的囊泡样小体。作为一种重要的细胞间信息传递分子及遗传物质传递载体,外泌体内含有蛋白质、RNA等多种活性物质,广泛分布于血液、尿液等体液中。目前发现多种类型细胞均可产生外泌体,尤其是间充质干细胞（MSCs）被认为是产生外泌体能力最强的细胞,并且MSCs源性外泌体（MSC-exosomes）与MSCs同样具有向炎症组织及肿瘤组织迁移的特性,为肿瘤治疗提供了一种新思路。由此,本文将从MSC-exosomes生物学特性、分离鉴定方法、肿瘤治疗潜能三方面进行综述。     

外泌体非编码RNA在非小细胞肺癌获得性耐药中的研究进展

非小细胞肺癌(non-small cell lung cancer,NSCLC)是肺癌中最常见的类型,对化疗及靶向药物的获得性耐药严重影响NSCLC患者的生存期,NSCLC获得性耐药机制复杂,确切机制仍不清楚.肿瘤来源或与肿瘤相关的外泌体是参与调控NSCLC获得性耐药的重要机制,可以通过传递核酸、蛋白质等赋予敏感细胞耐...