乳腺癌干细胞VEGF表达的实验研究

目的探讨乳腺癌干细胞血管内皮生长因子（Vascular endothelial growth factor,VEGF）的表达及意义。方法应用流式细胞分选技术从乳腺癌细胞株MCF-7细胞分离乳腺癌干细胞和非干细胞,采用Northern blot技术测定干细胞与非干细胞VEGF表达情况。结果与乳腺癌非干细胞相比,乳腺癌干细胞VEGF表达水平明显增强。结论乳腺癌干细胞可通过高表达VEGF增强转移能力,是乳腺癌转移的关键因素之一。     

Tumor stem cell niches: a new functional framework for the action of anticancer drugs

Newer treatments of advanced human cancer increasingly rely on combinations of drugs that have quite different actions yet unexpectedly potentiate each other's effects. Recent research in stem cell biology suggests a model for tumors in which tumor growth is governed by the generation of cells from tumor cell niches rather than from the population as a whole. Each niche contains a population of tumor stem cells supported by a closely associated vascular bed comprising mesenchyme-derived cells and an extracellular matrix. Division of tumor stem cells is asymmetric in the sense that some daughter cells are always retained within the niche while others leave the niche to proliferate further and eventually die. One important potential difference between normal and tumor stem cell niches is that while most normal stem cells are in a non-proliferating or G(0)-state, tumor stem cells are continuously in cycle. Combinations of cytotoxic drugs and antagonists of survival factors to reduce the stem cell population may require the addition of vascular disrupting agents to compromise the function of the tumor cell niche. As well as providing opportunities for new drug discovery, this model of tumor growth also presents challenges as to how the contributions of individual drugs in a combination might be assessed in individual patients.     

Chemical biology in stem cell research

Stem cells are offering a considerable range of prospects to the biomedical research including novel platforms for disease models and drug discovery tools to cell transplantation and regenerative therapies. However, there are several obstacles to overcome to bring these potentials into reality. First, robust methods to maintain stem cells in the pluripotent state should be established and factors that are required to direct stem cell fate into a particular lineage should be elucidated. Second, both allogeneic rejection following transplantation and limited cell availability issues must be circumvented. These challenges are being addressed, at least in part, through the identification of a group of chemicals (small molecules) that possess novel activities on stem cell biology. For example, small molecules can be used both in vitro and/or in vivo as tools to promote proliferation of stem cells (self-renewal), to direct stem cells to a lineage specific patterns (differentiation), or to reprogram somatic cells to a more undifferentiated state (de-differentiation or reprogramming). These molecules, in turn, have provided new insights into the signaling mechanisms that regulate stem cell biology, and may eventually lead to effective therapies in regenerative medicine. In this review, we will introduce recent findings with regards to small molecules and their impact on stem cell self-renewal and differentiation.     

Targeting IL-8 signalling to inhibit breast cancer stem cell activity

Although survival from breast cancer has improved significantly over the past 20 years, disease recurrence remains a significant clinical problem. The concept of stem-like cells in cancer has been gaining currency over the last decade or so, since evidence for stem cell activity in human leukaemia and solid tumours, including breast cancer, was first published. Evidence indicates that this sub-population of cells, known as cancer stem-like cells (CSCs), is responsible for driving tumour formation and disease progression. In breast cancer, there is good evidence that CSCs are intrinsically resistant to conventional chemo-, radio- and endocrine therapies. By evading the effects of these treatments, CSCs are held culpable for disease recurrence. Hence, in order to improve treatment there is a need to develop CSC-targeted therapies. Interleukin-8 (IL-8), an inflammatory cytokine, is upregulated in breast cancer and associated with poor prognostic factors. Accumulating evidence demonstrates that IL-8, through its receptors CXCR1/2, is an important regulator of breast CSC activity. Inhibiting CXCR1/2 signalling has proved efficacious in pre-clinical models of breast cancer providing a good rationale for targeting CXCR1/2 clinically. Here, we discuss the role of IL-8 in breast CSC regulation and development of novel therapies to target CXCR1/2 signalling in breast cancer.     

肿瘤干细胞靶向治疗

多种肿瘤中都存在肿瘤干细胞(cancer stem cell,CSC),这部分细胞具有自我更新能力和分化潜能,是肿瘤生长、增殖和转移的根源。此外,肿瘤干细胞具有正常干细胞的自我保护特性,如有效的DNA修复、高表达多药耐药型膜转运蛋白以及处于相对静止状态及拥有特定的微环境,使其能够逃逸现有的肿瘤治疗手段,导致肿瘤复发。针对这些保护机制,并利用肿瘤干细胞与正常干细胞的之间的差异进行靶向治疗,可能达到根治肿瘤的疗效。     

Biomaterials for stem cell differentiation

The promise of cellular therapy lies in the repair of damaged organs and tissues in vivo as well as generating tissue constructs in vitro for subsequent transplantation. Unfortunately, the lack of available donor cell sources limits its ultimate clinical applicability. Stem cells are a natural choice for cell therapy due to their pluripotent nature and self-renewal capacity. Creating reserves of undifferentiated stem cells and subsequently driving their differentiation to a lineage of choice in an efficient and scalable manner is critical for the ultimate clinical success of cellular therapeutics. In recent years, a variety of biomaterials have been incorporated in stem cell cultures, primarily to provide a conducive microenvironment for their growth and differentiation and to ultimately mimic the stem cell niche. In this review, we examine applications of natural and synthetic materials, their modifications as well as various culture conditions for maintenance and lineage-specific differentiation of embryonic and adult stem cells.     

Genetics of breast cancer

Breast cancer has all the hallmarks of a multistep genetic disease. Somatic and germ-line mutations have been described in several tumor suppressor genes, and oncogenes are found to be amplified. Genes in the ATM-CHK2-TP53 cell-cycle checkpoint pathway are mutated in relation to breast cancer, particularly TP53 at the somatic level. Germ-line mutations in BRCA1 and BRCA2, in which DNA repair function is interrupted, account for the majority of familial breast cancers. The mechanism behind the frequent instability of the genomes of breast cancer cells has been poorly understood, but recent functional findings on oncogenes and tumor suppressor genes have provided substantial information on the matter. Some recent developments in drug therapy are based on molecular and genomic findings about breast cancer pathogenesis.     

肿瘤干细胞的研究进展

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,越来越多的证据提示肿瘤中某些细胞具有干细胞特性,并提出了肿瘤干细胞的学说,认为肿瘤的生长、转移以及耐药等均于肿瘤干细胞的关系密切.该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.     

SMARCAD1 knockdown uncovers its role in breast cancer cell migration,invasion, and metastasis

Objective: Breast cancer is the most common cancer seen in women worldwide and breast cancer patients are at high risk of recurrence in the form of metastatic disease. Identification of genes associated with invasion and metastasis is crucial in order to develop novel anti-metastasis targeted therapy. It has been demonstrated that the DEAD-BOX helicase DP103 was implicated in breast cancer invasion and metastasis. SMARCAD1 is also a DEAD/H box-containing helicase, suggested to play a role in genetic instability. However, its involvement in cancer migration, invasion, and metastasis has never been explored.

Research design and methods: Using two different designs of shRNA targeting SMARCAD1, we investigated the impact of SMARCAD1 knockdown on the migration, invasion, and metastasis potential of the breast cancer cells MDA-MB-231 and T47D.

Results: We observed that SMARCAD1 knockdown in the invasive breast cancer cells MDA-MB-231, unlike in the non-invasive breast cancer cells T47D, was associated with an increased cell-cell adhesion and a significant decrease in cell migration, invasion, and metastasis due at least in part to a strong inhibition of STAT3 phosphorylation.

Conclusions: These results indicate that SMARCAD1 is involved in breast cancer metastasis and can be a promising target for metastatic breast cancer therapy.     

条件性重编程技术分离培养人原代乳腺癌干细胞

目的 应用条件性重编程细胞(Conditionally Reprogrammed Cells,CRCs)技术建立高效、稳定的人乳腺癌千细胞体外培养,建立潜在的乳腺癌干细胞靶向药研究模型.方法 收集人乳腺癌组织样本,采用CRCs技术分离培养原代乳腺癌细胞,用CD24免疫磁珠标记原代乳腺癌细胞后使用磁性细胞分选仪分选出乳腺...     

乳腺癌干细胞分选方法研究进展

乳腺癌干细胞是来源于正常乳腺干细胞或分化乳腺细胞,具有自我更新能力、分化能力、致瘤性特征及对放疗、化疗、内分泌治疗抵抗的乳腺癌细胞。目前分离乳腺癌干细胞的方法主要有CD44＋CD24-／lowLin-、乙醛脱氢酶1（ALDH1）、乳腺球、侧群细胞、DNA标记滞留细胞及改良分选方法等。本文将就近年来乳腺癌干细胞分选方法的研究进展做一综述。     

Increased PD‐L1 expression in breast and colon cancer stem cells

Here we report the expression of programmed cell death ligand 1/2 (PD‐L1/L2) in breast and colon cancer stem cells (CSCs). The stemness of these cells was confirmed by their surface markers. Using flow cytometry analysis we demonstrated that PD‐L1 expression was higher in CSCs of both cancers compared to non‐stem like cancer cells. Consistent with this, detection of cellular PD‐L1 proteins by western blot assay also showed increased PD‐L1 protein in CSCs. In contrast, only trace amounts of PD‐L2 were detected in CSCs of both cancers. Our results suggest that breast and colon cancers may be sensitive to PD1/PD‐L1 immunotherapy and thus warrant further investigations of CSC targeted PD1/PD‐L1 therapy.     

Artificial hematopoietic stem cell niche: bioscaffolds to microfluidics to mathematical simulations

Due to the recent advancements in stem cell biology and engineering, scientists have been increasingly interested in creating in vitro niches for embryonic and adult stem cells, and, following induction and differentiation with the appropriate media, the production of large scale blood production. This artificially created niche for hematopoietic cells will be composed of three materials: the stem cells themselves, the scaffold surrounding the stem cell, and the media used to expand and differentiate the stem cells. This paper will examine the recent advancements in technology for each of these relating to the development of an artificial stem cell niche. Many key aspects of the artificial niche need to be improved on before we can scale up the engineered device for large scale blood production including more efficient methods of retrieval of the embroid bodies produced from the microfluidic channels. The current state of experimental methods such as these as well as relevant discoveries in related fields that could be applied to artificial niche technology is described in this paper. Furthermore, we present a mathematical model to describe cell expansion in the artificial hematopoietic stem cell niche in order to design and optimize a scaled-up bioreactor. The mathematical model describes the dynamics of expansion, and maintenance of homeostasis in the bioreactor.     

Current concepts in adult stem cell therapy for stroke

Acute ischemic stroke causes a disturbance of neuronal circuitry and disruption of the blood-brain-barrier that can lead to functional disabilities. At present, thrombolytic therapy inducing recanalization of the occluded vessels in the cerebral infarcted area is a commonly used therapeutic strategy. However, only a minority of patients have timely access to this kind of therapy. Therefore, finding other techniques to effectively treat stroke patients is an important research goal. Stem cell therapies, such as adult stem cell transplantation, are promising strategies for the treatment of stroke. Preclinical experimental studies have included the application of human stem cells from various sources including the brain, bone marrow, umbilical cord, and adipose tissue. This review provides an update on current preclinical cell-therapies for stroke, focusing on stem cells derived from adult sources.     

表没食子儿茶素没食子酸酯抗乳腺癌作用机制的研究进展

乳腺癌是女性最常见的恶性肿瘤，其发病率呈逐年上升趋势。表没食子儿茶素没食子酸酯（EGCG）是茶叶中的主要活性成分之一，具有抗氧化、抗炎症、保护心血管、预防糖尿病及抗肿瘤等功效。近年来，多项体内和体外研究表明EGCG通过抑制细胞增殖、血管生成、干性、侵袭转移及促进凋亡等方式抑制乳腺癌的发生发展。主要对EGCG抑制乳腺癌的分子机制进行综述，为乳腺癌的防治提供新的线索。     

Acetaminophen-induced differentiation of human breast cancer stem cells and inhibition of tumor xenograft growth in mice

It is now believed that cancer stem cells (CSCs) that are resistant to chemotherapy due to their undifferentiated nature drive tumor growth, metastasis and relapse, so development of drugs that induce differentiation of CSCs should have a profound impact on cancer eradication. In this study, we screened medicines that are already in clinical use for drugs that induce differentiation of CSCs. We used MDA-MB-231, a human breast cancer cell line that contains cancer stem cell-like cells. We found that acetaminophen, an anti-inflammatory, antipyretic and analgesic drug, induces differentiation of MDA-MB-231 cells. Differentiation was assessed by observing alterations in cell shape and expression of differentiated and undifferentiated cell markers, a decrease in cell invasion activity and an increase in susceptibility to anti-tumor drugs. This increased susceptibility seems to involve suppression of expression of multidrug efflux pumps. We also suggest that this induction of differentiation is mediated by inhibition of a Wnt/β-catenin canonical signaling pathway. Treatment of MDA-MB-231 cells with acetaminophen in vitro resulted in the loss of their tumorigenic ability in nude mice. Furthermore, administration of acetaminophen inhibited the growth of tumor xenografts of MDA-MB-231 cells in both the presence and absence of simultaneous administration of doxorubicine, a typical anti-tumor drug for breast cancer. Analysis with various acetaminophen derivatives revealed that o-acetamidophenol has a similar differentiation-inducing activity and a similar inhibitory effect on tumor xenograft growth. These results suggest that acetaminophen may be beneficial for breast cancer chemotherapy by inducing the differentiation of CSCs.     

Preclinical development of cancer stem cell drugs

Background: Despite recent progress in cancer treatment, the current cancer chemotherapy can mainly produce remission but often fails to cure cancer due to the existence of cancer stem cells. The emerging cancer stem cell hypothesis offers new insight into the failure of current cancer drugs and suggests new approaches for improved understanding of cancer biology and cancer drug development. Objective: In this review, we discuss the concept of cancer stem cells, origin of cancer stem cells and different approaches for isolating or enriching cancer stem cells. We also review the resistance of cancer stem cells to standard chemotherapy and radiation therapy and potential mechanisms for the resistance. Finally, based on the current knowledge on cancer stem cells, we discuss potential approaches for developing new drugs that target cancer stem cells and propose new methods for evaluation of cancer stem cell drugs. Conclusion: Improved cancer treatment is likely to be achieved by a combination of drugs that kill both replicating cancer cells and more quiescent cancer stem cells.