肺癌干细胞

现有研究表明,在肺癌中与于细胞功能相关的wnt、Notch和Hedgehog信号通路被异常激活,它们与肺癌干细胞的高致瘤性、高转移性、耐药性等特性密切相关。多项研究显示肺癌干细胞群高度表达肿瘤耐药蛋白并且对放化疗明显耐受。因此,如何靶向治疗肺癌干细胞,最终根治肺癌,正逐渐成为肿瘤靶向治疗研究中的热点。     

乳腺癌干细胞研究现状

肿瘤干细胞理论认为肿瘤可能是由肿瘤干细胞和其所处微环境产生,而肿瘤干细胞由正常干细胞突变而来.乳腺癌干细胞是第一个在实体瘤中被鉴定的肿瘤干细胞,人们采用多种策略成功分离出乳腺癌干细胞,对其生物学行为的认识正逐渐深入.乳腺癌干细胞的自我更新、分化等特性受到微环境和许多信号转导通路的调控.如何靶向治疗乳腺癌干细胞,最终根治乳腺癌,正逐渐成为肿瘤靶向治疗研究的一个热点.     

卵巢癌肿瘤干细胞的研究进展

卵巢癌肿瘤干细胞是从卵巢癌组织及癌性腹腔积液中分离出的一小群具有自我更新和多向分化潜能的细胞,与卵巢癌的高复发率、强耐药性密切相关.因此治疗晚期卵巢癌的关键在于研究以肿瘤干细胞为靶向的治疗方法.随着对卵巢癌肿瘤干细胞的成功分离鉴定,为卵巢癌的基因靶向治疗提供了可能.     

肿瘤干细胞疫苗的研究进展

目前已知的绝大多数癌症治疗方法如化疗、放疗、免疫靶向治疗等主要以肿瘤细胞为靶目标,但很多肿瘤并不能被完全治愈且治疗后伴随很多并发症。一群高度耐药的肿瘤细胞能够使肿瘤重新聚集并转移到新的部位,使肿瘤继续发生发展。如果可以基于它们的表型或功能特征来鉴定具有干细胞样特征的癌细胞,从而找到肿瘤干细胞特异性抗原制成干细胞疫苗,进而激活机体内特异的免疫应答,以达到靶向清除肿瘤干细胞的目的,就能一定程度上控制肿瘤的复发及转移,杀灭肿瘤干细胞甚至可以消除肿瘤对放化疗的拮抗性及耐药性。因此肿瘤干细胞疫苗即靶向肿瘤干细胞的主动免疫疗法的研究与发展对恶性难治性肿瘤的治疗有着重要意义,本篇综述将对近年来肿瘤干细胞及其疫苗的发现、发展与研究结果进行概述。     

肿瘤干细胞的研究进展

肿瘤干细胞(cancer stem cell)是存在于肿瘤组织中的一小部分具有干细胞性质的细胞群体.近年来,越来越多的学者认为肿瘤干细胞的残存是恶性肿瘤复发的根源.随着研究的深入,肿瘤干细胞的靶向治疗为恶性肿瘤的治疗带来了新的希望.     

间质干细胞与肿瘤转移

间质干细胞(MSC)能够向炎症和肿瘤部位趋化,参与肿瘤微环境的组成,对肿瘤的生长和转移起重要作用.对间质干细胞在肿瘤生长与转移中的作用及机制研究将为肿瘤发生及肿瘤靶向治疗提供新的思路.     

肿瘤干细胞的调控机制研究进展

肿瘤干细胞是一群未分化、具有自我更新、多系分化潜能的细胞.现有的研究表明肿瘤干细胞的自我更新、分化、转移、致瘤性受到Wnt、Notch、Hedgehog、CXCR4-SDF-1轴、PTEN等多种信号传导通路的调控.而肿瘤干细胞与间充质干细胞分别构成肿瘤的上皮部分与间质部分,它们之间可能也存在着相互调控.深入研究肿瘤干细胞的调控机制,对于开发以肿瘤干细胞为靶点的新型靶向治疗药物,最终根除肿瘤具有重要意义.     

肿瘤干细胞传统治疗抵抗与靶向治疗

近年来,不断有资料表明,肿瘤干细胞和正常干细胞具有相似的性质.肿瘤干细胞导致肿瘤的发生、复发及转移.肿瘤干细胞对传统治疗方法的抵抗是肿瘤治疗失败的主要原因.同时,肿瘤干细胞位于特定的微环境中,肿瘤干细胞与微环境的相互作用显著影响肿瘤的进程.本文针对肿瘤干细胞及其微环境的靶向治疗做一综述.期望为肿瘤治疗带来新的思路.     

肿瘤微环境与肺癌相关性研究进展

肺癌是我国最常见的恶性肿瘤之一,发病率逐年增加并呈年轻化趋势.分子生物学的发展及靶向治疗应用成为肺癌治疗的里程碑,但仍有部分肺癌患者在治疗的早期就出现转移.近年大量研究发现肿瘤微环境在肺癌侵袭转移过程起着重要作用.全文就肿瘤微环境的概念、作用机制及其与肺癌复发转移及治疗的相互关系作一概述.     

肿瘤干细胞相关机制及靶向肿瘤干细胞治疗研究进展

肿瘤干细胞(cancer stem cells,CSCs)是肿瘤细胞中存在的小部分具有无限自我更新和多向分化潜能的细胞亚群,是肿瘤形成、复发、恶性转移和耐受放化疗性的细胞学根源.肿瘤干细胞的相关研究为肿瘤的治疗提供了新的思路,肿瘤干细胞靶向治疗可能成为肿瘤根治的希望.然而,目前对肿瘤干细胞的调控机制还不甚清楚,基于调控肿瘤干细胞的抗肿瘤治疗还有待成熟.本综述旨在总结近年来有关调控肿瘤干细胞及相关肿瘤治疗的主要研究进展,并对基于肿瘤干细胞调控的抗肿瘤治疗进行讨论和展望.     

Intracellular signals of lung cancer cells as possible therapeutic targets

In recent years, several molecularly targeted therapies have been developed as part of lung cancer treatment; they have produced dramatically good results. However, among the many oncogenes that have been identified to be involved in the development of lung cancers, a number of oncogenes are not covered by these advanced therapies. For the treatment of lung cancers, which is a group of heterogeneous diseases, persistent effort in developing individual therapies based on the respective causal genes is important. In addition, for the development of a novel therapy, identification of the lung epithelial stem cells and the origin cells of lung cancer, and understanding about candidate cancer stem cells in lung cancer tissues, their intracellular signaling pathways, and the mechanism of dysregulation of the pathways in cancer cells are extremely important. However, the development of drug resistance by cancer cells, despite the use of molecularly targeted drugs for the causal genes, thus obstructing treatment, is a well‐known phenomenon. In this article, we discuss major causal genes of lung cancers and intracellular signaling pathways involving those genes, and review studies on origin and stem cells of lung cancers, as well as the possibility of developing molecularly targeted therapies based on these studies.     

Do stem-like cells play a role in drug resistance of sarcomas?

Stem cells are defined by their unique characteristics, which include their abilities to self-renew and differentiate. Normal somatic stem cells have been isolated from various tissues such as bone marrow, adipose tissue, mammary glands and the nervous system. They are considered naturally resistant to chemotherapeutic agents because they express high levels of membrane transporter molecules, detoxifying enzymes and DNA repair proteins. Several recent studies have identified the presence of side populations in various cancer tissues, the so-called ‘cancer stem cells’, which are defined as the counterparts of stem cells in tumor tissues. These cancer stem cells possess stem-like properties, such as self-renewal and differentiation abilities, as well as playing a role in tumor initiation. Most sarcomas, which are thought to originate from mesenchymal stem cells, are highly malignant and approximately 30–40% of them show local and/or distant relapse (metastasis), even in the case of relatively chemosensitive tumors such as osteosarcomas and Ewing sarcomas. Several studies have suggested the presence of stem-like cell populations in sarcomas, based on their tumorigenicity and drug resistance. This review explores the issues of drug resistance of cancer stem cells in sarcomas and the possibilities of targeting cancer stem cells for the future treatment of sarcomas.     

Breast cancer stem cells as last soldiers eluding therapeutic burn: A hard nut to crack

Cancer stem cells (CSCs) are found in many cancer types, including breast carcinoma. Breast cancer stem cells (BCSCs) are considered as seed of cancer formation and they are associated with metastasis and genotoxic drug resistance. Several studies highlighted the presence of BCSCs in tumor microenvironment and they are accentuated with several carcinoma events including metastasis and resistance to genotoxic drugs and they also rebound after genotoxic burn. Stemness properties of a small population of cells in carcinoma have provided clues regarding the role of tumor microenvironment in tumor pathophysiology. Hence, insights in cancer stem cell biology with respect to molecular signaling, genetics and epigenetic behavior of CSCs have been used to modulate tumor drug resistance due to genotoxic drugs and signaling protein inhibitors. This review summarizes major scientific breakthroughs in understanding the contribution of BCSCs towards tumor's capability to endure destruction inflicted by molecular as well as genotoxic drugs.     

Lung cancer stem cells: Tumor biology and clinical implications

The concept of cancer stem cells (CSC) has drawn great attention from researchers in both molecular and clinical fields as has brought a new perspective to the way we manage cancer. CSC have several characteristics that are shared by the properties of normal stem cells, such as differentiation, self-renewal and homeostatic control. However, CSC have the capacity to both divide and expand the CSC pool and to differentiate into heterogeneous non-tumorigenic cancer cells. Even more, CSC have an inherent high resistance to chemotherapeutic agents that leads to recurrence and poor long-term survival, especially in lung cancer patients. CSC-targeting agents are now undergoing in vitro and in vivo studies, some of which have provided promising results for further clinical studies setting. In this article we review the concept of CSC from the perspective of tumor biology, including the origin of CSC and its biomarkers. As lung cancer is the leading cause of cancer-related deaths worldwide, we focus on the properties and clinical implications of lung CSC.     

Therapy‐induced enrichment of putative lung cancer stem‐like cells

Tumour drug resistance is a major issue in the management of lung cancer patients as almost all lung tumours are either intrinsically resistant or quickly develop acquired resistance to chemotherapeutic drugs. Cancer drug resistance has recently been linked, at least in part, to the existence of cancer stem‐like cells (CSLCs), a small sub‐population of cells within the tumour that possess stem‐like properties. CSLCs are often isolated by fluorescence activated cell sorting (FACS) according to the expression of certain stem‐like cell membrane markers. Conflicting results regarding the specificity of particular stem cell surface markers for isolating CSLCs have, however, been recently reported. Therefore, alternative strategies enabling the identification and study of CSLCs should be considered, particularly in tumour types where appropriate stem cell markers are not well established and validated, like in lung cancer. In this article, we review data indicating therapy‐selection as a valid approach for putative lung CSLCs enrichment. We believe that this strategy would be determinant for correctly assessing and characterising the sub‐populations of CSLCs that are able to survive chemo or radiotherapy regimens and, at the same time, also have the ability to recapitulate and sustain tumour growth. Using therapy‐induced enrichment of CSLCs may, therefore, prove to be an extremely useful method for studying CSLCs and provide new clues regarding potential therapeutic targets for their efficient elimination, which will undoubtedly play a decisive role in improving lung cancer patients' survival.     

南方红豆杉水提物逆转非小细胞肺癌干细胞耐药作用的实验

目的 研究南方红豆杉水提物逆转非小细胞肺癌干细胞耐药作用的机制。方法 选取人非小细胞肺癌H460细胞为实验细胞,以侧群细胞及细胞表面标志物鉴定法筛选出其中的干细胞;CCK8（cell counting kit-8）法检测红豆杉水提物对H460干细胞的毒性,并检测红豆杉水提物逆转H460干细胞对顺铂的耐药性;流式细胞术（flow cytometry, FCM）检测红豆杉水提物逆转H460干细胞耐药的作用机制。结果 红豆杉水提物对H460干细胞有细胞毒性,测得H460干细胞的IC50为1 449.5 μg/ml;用红豆杉水提物预处理后的H460干细胞进行实验发现,顺铂的抗肿瘤效应明显增强,其作用机制为抑制细胞膜上的P-gp蛋白来降低有效药物排出量。结论 南方红豆杉水提物能够较强的逆转非小细胞肺癌干细胞的耐药性。     

Role of Notch signaling in colon homeostasis and carcinogenesis

Colorectal cancer is a leading cause of cancer-related deaths world-wide. Despite the development of new anticancer agents, there will be an estimated 150,000 new cases and 50,000 deaths associated with this disease during the next year.((1)) This is due, in part, to the limitations of chemotherapy, resulting from drug resistance and organ system toxicities. To overcome the inherent limitations associated with standard chemotherapy techniques, the development of novel drug targets is of utmost importance in combating this disease. There is accumulating evidence that a small fraction of cancer cells, referred to as cancer stem cells, may play a critical role in the pathogenesis of this disease. In fact, the identification of cancer stem cells can be accomplished based on the expression of surface markers associated with a cancer stem-like phenotype. This stem-like phenotype includes indefinite self-replication, pluripotency, and most importantly, resistance to chemotherapeutics. Therefore, understanding the properties of cancer stem cells may ultimately lead to new therapeutic approaches. Recently, several studies have shown that Notch signaling is critical in maintaining cancer stem cell properties. This review provides a summary of colonic crypt organization and colon carcinogenesis with a focus on stem cells. Moreover, we discuss novel therapeutic strategies that are under development for targeting Notch signaling in cancer stem cells.     

ALDH-positive lung cancer stem cells confer resistance to epidermal growth factor receptor tyrosine kinase inhibitors

Molecular targeting therapeutics, such as EGFR tyrosine kinase inhibitors (TKIs), are important treatment strategies for lung cancer. Currently, the major challenge confronting targeted cancer therapies is the development of resistance. Cancer stem cells (CSCs) represent a rare population of undifferentiated tumorigenic cells responsible for tumor initiation, maintenance and spreading. Resistance to conventional chemotherapeutic drugs is a common characteristic of CSCs. However, the issue of whether CSCs contribute to EGFR TKI resistance in lung cancer is yet to be established. In the current study, we explored the association of ALDH1A1 expression with EGFR TKI resistance in lung cancer stem cells. ALDH1A1-positive lung cancer cells displayed resistance to gefitinib, compared to ALDH1A1-negative lung cancer cells. Moreover, PC9/gef cells (gefitinib-resistant lung cancer cells) presented a higher proportion of ALDH1A1-positive cells, compared to PC9 cells (gefitinib-sensitive lung cancer cells). Clinical sample studies were consistent with results from cell culture model systems showing that lung cancer cells with resistance to EGFR TKI and chemotherapy drugs contain significantly increased proportions of ALDH1A1-positive cells. These findings collectively suggest that ALDH1A1 positivity in cancer stem cells confers resistance to EGFR TKI in lung cancer.     

Molecular characterisation of side population cells with cancer stem cell-like characteristics in small-cell lung cancer

Background:

Side population (SP) fraction cells, identified by efflux of Hoechst dye, are present in virtually all normal and malignant tissues. The relationship between SP cells, drug resistance and cancer stem cells is poorly understood. Small-cell lung cancer (SCLC) is a highly aggressive human tumour with a 5-year survival rate of <10%. These features suggest enrichment in cancer stem cells.

Methods and results:

We examined several SCLC cell lines and found that they contain a consistent SP fraction that comprises <1% of the bulk population. Side population cells have higher proliferative capacity in vitro, efficient self-renewal and reduced cell surface expression of neuronal differentiation markers, CD56 and CD90, as compared with non-SP cells. Previous reports indicated that several thousand SP cells from non-small-cell lung cancer are required to form tumours in mice. In contrast, as few as 50 SP cells from H146 and H526 SCLC cell lines rapidly reconstituted tumours. Whereas non-SP cells formed fewer and slower-growing tumours, SP cells over-expressed many genes associated with cancer stem cell and drug resistance: ABCG2, FGF1, IGF1, MYC, SOX1/2, WNT1, as well as genes involved in angiogenesis, Notch and Hedgehog pathways.

Conclusions:

Side population cells from SCLC are highly enriched in tumourigenic cells and are characterised by a specific stem cell-associated gene expression signature. This gene signature may be used for development of targeted therapies for this rapidly fatal tumour.