Spontaneous fusion between cancer cells and endothelial cells

Endothelial cells line the inside of blood and lymphatic vessels, and cancer cells must cross this barrier, first to gain access to the circulation, and, second, to exit and metastasize. How this occurs is incompletely understood. We now demonstrate that human cancer cells are able to fuse with endothelial cells to form hybrid cells displaying proteins and chromosomal markers characteristic of both parent cells. The hybrid cells are viable and capable of undergoing mitosis. Fusions between cancer cells and endothelial cells were shown to occur both in vitro, in co-cultures of human breast cancer cells and endothelial cells, and in vivo, following intravascular dissemination of human breast cancer cells in nude mice. These observations demonstrate a new type of cancer-endothelial cell interaction that may be of fundamental importance to the process of metastasis.Received 10 May 2004; received after revision 21 June 2004; accepted 2 July 2004     

The balance between immunity and tolerance: The role of Langerhans cells

Langerhans cells are immature skin-homing dendritic cells that furnish the epidermis with an immune surveillance system, and translate information between the internal and external milieu. Dendritic cells, in particular Langerhans cells, are gaining prominence as one of the potential principal players orchestrating the decision between immunity and tolerance. Langerhans cells capture aberrant self-antigen and pathogen-derived antigen for display to the efferent immune response. Recent evidence suggests redundancy in the antigen-presenting function of Langerhans cells, with dermal dendritic subsets capable of fulfilling an analogous role. There is mounting evidence that Langerhans cells can cross-prime T cells to recognize antigens. Langerhans cells are proposed to stimulate T regulatory cells, and are implicated in the pathogenesis of cutaneous T cell lymphoma.The phenotype of Langerhans cells, which may be tolerogenic or immunogenic, appears to depend on their state of maturity, inciting immunogen and cytokine environment, offering the potential for manipulation in immunotherapy. Received 6 August 2008; received after revision 18 September 2008; accepted 13 October 2008     

胃癌侧群细胞耐药性研究及干细胞相关基因检测

目的研究胃癌侧群（Side Population,sP）细胞对化疗药物5-Fu（氟尿嘧啶）的耐药性及可能机制,并检测干细胞相关基因Nanog、Musashi-1及cD44的表达情况。方法选择人胃癌细胞株sGc-7901,以荧光染料H0echst 33342染色,维拉帕米桔抗对照,应用流式细胞仪分选sP细胞和nonsP细胞。细胞耐药实验比较sP细胞与nonsP细胞对化疗药物5．Fu的耐药性差异;westem_h10t检测ABcG2和bcl-2蛋白表达情况;流式细胞仪分析细胞周期;荧光定量PcR检测两组细胞中干细胞相关基因Nanog、Musashi-1及cD44mRNA的表达差异。结果胃癌细胞株sGc．790l中sP细胞的比例为2．8％,sP细胞对5-Fu的耐药存活率明显高于non-sP细胞（P〈0．05）,与nonsP细胞相比,sP细胞高表达耐药蛋白ABcG2和抗凋亡蛋白bcl-2,有更多的细胞处于c0／G1期（P〈0．05）,并高表达干细胞相关基因Musashi-1和cD44。结论胃癌sGC_7901细胞株中sP细胞对化疗药物5．Fu的耐药性明显高于nonsP细胞,其耐药机制可能与sP细胞高表达耐药蛋白ABcG2和抗凋亡蛋白bcl-2,有更多细胞处于G0／Gl期有关;Musashi-1和cD44可能是相对特异性的胃癌干细胞标志物。     

Identification of cytotoxic cells responsible for lysis of target cells pretreated with concanavalin A in spleen populations of pregnant mice with suppressive activity]

During an alloimmunization, killer cells which lyse target cells only in the presence of a lectin are generated. That these cells, as well as suppressive cells, share immunocytological properties with specific killer cells, leads to the hypothesis that these cells may be concerned with the mechanism of immunosuppression. Two experimental results presented in this paper are consistent with this hypothesis: 1) Spleens from H-2k mice pregnant by H-2d males which bear a high suppressive activity also contain a relatively large number of killer cells having the ability to lyse Concanavalin A treated target cells and 2) supernatants of suppressive systems generated through an MLC block the cytolysis of specific target cells by the bound killer cells.     

Endothelial cells as antigen-presenting cells: role in human transplant rejection

The immunological properties of human endothelial cells suggest they perform a pivotal role in acute and chronic rejection following solid organ transplantation. In this review the basic features of acute and chronic rejection are described as are the cellular and molecular requirements for antigen presentation. Traditionally, antigen-presenting cells are considered to be bone marrow-derived cells. However, these conclusions have been derived from rodent models of allograft rejection where bone marrow-derived passenger leukocytes are the only source of donor major histocompatibility complex (MHC) class II in the grafted organ. In contrast, in humans, virtually all the microvascular and small vessel endothelial cells are ‘constitutively’ positive for MHC class II antigens. The phenotypic properties of human endothelial cells, their response to cytokines and their ability to stimulate resting T cells are described. Unlike bone marrow-derived antigen presenting cells (APCs), which utilise B7/CD28 interactions, human endothelial cells utilise lymphocyte function antigen 3 (LFA3)/CD2 pathways to stimulate T cells. They activate a CD45RO + B7-independent subpopulation of T cells. Their effect on allogeneic T cells is compared with other non-bone marrow-derived cells such as fibroblasts, epithelial cells and smooth muscle cells, which are unable to stimulate resting T cells. Evidence is presented suggesting that release of MHC and non-human leukocyte antigens (HLA) from endothelial cells stimulates an alloantibody and autoimmune response leading to chronic rejection. Received 30 March 1998; received after revision 4 May 1998; accepted 4 May 1998     

In vivo matrix-guided human mesenchymal stem cells

Microfracture of subchondral bone results in intrinsic repair of cartilage defects. Stem or progenitor cells from bone marrow have been proposed to be involved in this regenerative process. Here, we demonstrate for the first time that mesenchymal stem (MS) cells can in fact be recovered from matrix material saturated with cells from bone marrow after microfracture. This also introduces a new technique for MS cell isolation during arthroscopic treatment. MS cells were phenotyped using specific cell surface antibodies. Differentiation of the MS cells into the adipogenic, chondrogenic and osteogenic lineage could be demonstrated by cultivation of MS cells as a monolayer, as micromass bodies or mesenchymal microspheres. This study demonstrates that MS cells can be attracted to a cartilage defect by guidance of a collagenous matrix after perforating subchondral bone. Protocols for application of MS cells in restoration of cartilage tissue include an initial invasive biopsy to obtain the MS cells and time-wasting in vitro proliferation and possibly differentiation of the cells before implantation. The new technique already includes attraction of MS cells to sites of cartilage defects and therefore may overcome the necessity of in vitro proliferation and differentiation of MS cells prior to transplantation. Received 3 November 2005; received after revision 15 December 2005; accepted 4 January 2006     

Functional inhibition of isolated pancreatic cells, new technic for the detection of macrophage cytotoxicity]

It is usually accepted that macrophages "activated" by lymphokines may be found cytotoxic against tumoral target cells but show no detectable cytotoxicity in in vitro tests using normal non tumoral cells as target cells. These data have been obtained mainly with the chromium-release test. The present paper describes a new test using normal isolated pancreatic cells as target cells and evaluating the effect of activated or non-activated macrophages on the insulin secretion response to glucose stimulation. The results show a striking decrease in this response following an 18-hr incubation of pancreatic islet cells with activated macrophages, as compared to that of the same cells incubated with control macrophages. This is clear evidence that activated macrophages may alter normal cells and suggests that their cytotoxic properties are not restricted to tumoral target cells.     

Secificity of mouse endocervical cell response progesterone: presence of receptors]

The mouse cervical cell response to progesterone, corticosterone, and androgens was studied in vitro and comparatively by grafts on males. Contrary to the exocervical cells which responded more or less to the three steroid hormones, the endocervical cells responded exclusively to progesterone even in an estrogen free system. This result suggests the existence in the mouse endocervical cells of specific receptors to progesterone and indicates that the squamons cells of the uterine cervix have a different response to steroid hormones depending on where these cells are located.     

The unique features of follicular T cell subsets

The germinal center (GC) reaction is critical for humoral immunity, but also contributes adversely to a variety of autoimmune diseases. While the major protective function of GCs is mediated by plasma cells and memory B cells, follicular helper T (TFH) cells represent a specialized T cell subset that provides essential help to the antigen-specific B cells in the form of membrane-bound ligands and secreted factors such as IL-21. Recent studies have revealed that TFH cells are capable of considerable functional diversity as well as possessing the ability to form memory cells. The molecular basis of this plasticity and heterogeneity is only now emerging. It has also become apparent that several other populations of follicular T cells exist, including natural killer T cells and regulatory T cells. In this review we will discuss the function of follicular T cells and interaction of these populations within the GC response.     

Effects of mistletoe (Viscum album L.) extracts on cultured tumor cells

Bacterially fermented mistletoe preparations (BFMP) were tested on rat hepatoma tissue culture (HTC) cells and human leukemia Molt 4 cells. A dose-dependent inhibition of the growth rate of the cells was observed. For both cell lines, cytostatic concentrations, expressed in weight of fresh plant, were 0.5 mg/ml culture medium for oak BFMP and 1 mg/ml for apple tree BFMP. However, the action of the two preparations was markedly different on each cell line. Non-viable HTC cells were not stained by trypan blue while non-viable Molt 4 cells were fully colored by this reagent. A lysis of cellular membranes of HTC cells was observed by electron microscopy. Furthermore, oak BFMP inhibited the growth of virus transformed 3T3-SV40 cells more than that of non-transformed 3T3 cells. In contrast to BFMP, non-fermented extracts and a purified mistletoe lectin showed a greater inhibition of the growth of Molt 4 cells than of HTC cells. Samples withdrawn at different times during fermentation gradually lost their inhibitory effect on the growth of Molt 4 cells while their action on HTC cells increased up to the 4th day of fermentation. These results are discussed in relation to the cytotoxic substances of mistletoe already characterized.     

Epithelial supporting cells can differentiate into outer hair cells and Deiters' cells in the cultured organ of Corti

The organ of Corti is a complex structure containing a single row of inner hair cells (IHCs) and three rows of outer hair cells (OHCs), supported respectively by one row of inner phalangeal cells and three rows of Deiters' cells. When fetal rat organ of Corti explants are cultured, supernumerary OHCs and supernumerary Deiters' cells are produced, without any additional cell proliferation. Analysis of semi- and ultrathin sections revealed that supernumerary OHCs are produced at the distal edge of the organ of Corti. Quantitative analysis of cell types present in the organ of Corti demonstrates that when the number of OHCs increases: (i) the total number of cells remains constant; (ii) the number of Deiters' cells increases; (iii) the number of tectal cells decreases and of Hensen's cells decreases. Using specific HC markers, i.e. jagged2 (Jag2) and Math1, we showed that in addition to existing OHCs, supernumerary OHCs, tectal cells and Hensen's cells expressed these markers in embryonic day 19 organ of Corti explants after 5 days in vitro. The results of this study suggest that Hensen's cells retain the capacity to differentiate into either tectal cells, which differentiate into OHCs, or into undertectal cells which differentiate into Deiters' cells. Received 15 May 2002; received after revision 18 July 2002; accepted 7 August 2002 RID="*" ID="*"Corresponding author.     

Description of the folliculo-stellate cells in the anterior hypophysis of the monkey Macacus irus]

Folliculo-stellar cells are present in the anterior lobe of hypophysis of the monkey Macacus irus. These cells limit strait cavities in which one can observe microvillosites at the apical pole of the cells. The folliculo-stellar cells possess long and thin fibers which insert themselves between different types of granular cells and sometimes extend to the peri-capillar regions. Numerous organelles are present in these folliculo-stellar cells, especially microfilaments.     

肝癌细胞系Hep3B中CD133+细胞亚群的分离及其特性的研究

目的研究CD133在人肝癌细胞系Hep3B中的表达以及CD133+细胞的体外增殖、自我更新及体内成瘤能力,初步探讨肝癌中CD133+细胞亚群的干细胞特性。方法流式细胞仪检测未分选的Hep3B细胞中CD133+细胞表达情况;免疫磁珠分选技术纯化CD133+肿瘤细胞;MTT法检测CD133+细胞体外增殖能力;无血清培养纯化...     

Syncytin is involved in breast cancer-endothelial cell fusions

Cancer cells can fuse spontaneously with normal host cells, including endothelial cells, and such fusions may strongly modulate the biological behaviour of tumors. However, the underlying mechanisms are unknown. We now show that human breast cancer cell lines and 63 out of 165 (38%) breast cancer specimens express syncytin, an endogenous retroviral envelope protein, previously implicated in fusions between placental trophoblast cells. Additionally, endothelial and cancer cells are shown to express ASCT-2, a receptor for syncytin. Syncytin antisense treatment decreases syncytin expression and inhibits fusions between breast cancer cells and endothelial cells. Moreover, a syncytin inhibitory peptide also inhibits fusions between cancer and endothelial cells. These results are the first to show that syncytin is expressed by human cancer cells and is involved in cancer-endothelial cell fusions. Received 2 May 2006; received after revision 7 June 2006; accepted 12 June 2006     

Breaking T cell tolerance to beta cell antigens by merocytic dendritic cells

In type 1 diabetes (T1D), a break in central and peripheral tolerance results in antigen-specific T cells destroying insulin-producing, pancreatic beta cells. Herein, we discuss the critical sub-population of dendritic cells responsible for mediating both the cross-presentation of islet antigen to CD8⁺ T cells and the direct presentation of beta cell antigen to CD4⁺ T cells. These cells, termed merocytic dendritic cells (mcDC), are more numerous in non-obese diabetic (NOD), and antigen-loaded mcDC rescue CD8⁺ T cells from peripheral anergy and deletion, and stimulate islet-reactive CD4⁺ T cells. When purified from the pancreatic lymph nodes of overtly diabetic NOD mice, mcDC can break peripheral T cell tolerance to beta cell antigens in vivo and induce rapid onset T cell-mediated T1D in young NOD mouse. Thus, the mcDC subset appears to represent the long-sought critical antigen-presenting cell responsible for breaking peripheral tolerance to beta cell antigen in vivo.     

Production of insulin-like growth factor I (IGF-I) and IGF-binding proteins by rat intestinal stromal cells in vitro

To determine if intestinal stromal cells secrete diffusible factors such as insulin-like growth factors (IGFs) capable of regulating epithelial cell growth in vitro, stromal cells were isolated by enzymatic digestion of rat intestine. Incorporation of [³H]thymidine into DNA and [¹⁴C]leucine into protein of IEC-6 cells, a model intestinal epithelial cell line, was significantly increased (two- to threefold) when the IEC-6 cells were co-cultured with stromal cells, relative to IEC-6 cells grown alone. Medium conditioned by stromal cells stimulated DNA synthesis of IEC-6 cells in a dose-dependent manner. Analysis of the conditioned medium revealed that intestinal stromal cells secreted IGF-I, but little IGF-II, in addition to an M _r 32,000 IGF-binding protein (IGFBP-2) and an IGFBP having M _r∼ 24,000. We conclude that rat intestinal stromal cells secrete one or more diffusible factors, which may include IGF-I and IGFBPs, capable of stimulating proliferation of IEC-6 cells in vitro. Received 25 August 1997; received after revision 7 November 1997; accepted 20 November 1997     

B Lymphocytes in obesity-related adipose tissue inflammation and insulin resistance

Obesity-related insulin resistance is a chronic inflammatory condition that often gives rise to type 2 diabetes (T2D). Much evidence supports a role for pro-inflammatory T cells and macrophages in promoting local inflammation in tissues such as visceral adipose tissue (VAT) leading to insulin resistance. More recently, B cells have emerged as an additional critical player in orchestrating these processes. B cells infiltrate VAT and display functional and phenotypic changes in response to diet-induced obesity. B cells contribute to insulin resistance by presenting antigens to T cells, secreting inflammatory cytokines, and producing pathogenic antibodies. B cell manipulation represents a novel approach to the treatment of obesity-related insulin resistance and potentially to the prevention of T2D. This review summarizes the roles of B cells in governing VAT inflammation and the mechanisms by which these cells contribute to altered glucose homeostasis in insulin resistance.     

A comparative analysis of the cell biology of senescence and aging

Various intracellular organelles, such as lysosomes, mitochondria, nuclei, and cytoskeletons, change during replicative senescence, but the utility of these changes as general markers of senescence and their significance with respect to functional alterations have not been comprehensively reviewed. Furthermore, the relevance of these alterations to cellular and functional changes in aging animals is poorly understood. In this paper, we review the studies that report these senescence-associated changes in various aging cells and their underlying mechanisms. Changes associated with lysosomes and mitochondria are found not only in cells undergoing replicative or induced senescence but also in postmitotic cells isolated from aged organisms. In contrast, other changes occur mainly in cells undergoing in vitro senescence. Comparison of age-related changes and their underlying mechanisms in in vitro senescent cells and aged postmitotic cells would reveal the relevance of replicative senescence to the physiological processes occurring in postmitotic cells as individuals age.     

人结肠癌CW-2干细胞获取方法研究

目的运用3种不同的方法分离纯化人结肠癌CW-2干细胞,并对其分离纯化效率进行比较,探讨获得癌干细胞的有效方法。方法采用单纯无血清悬浮培养、无血清悬浮培养联合化疗药物、流式细胞分选技术分别富集人结肠癌细胞株CW-2干细胞;然后运用流式细胞术、NOD—SCID小鼠致瘤实验和Transwell侵袭实验分析比较3种方法的富集效率。结果无血清悬浮培养细胞．无血清悬浮培养联合化疗药物处理细胞和流式细胞仪分选技术分选后细胞中具有结肠癌干细胞特性的CD44＋EPCAM_细胞分别为（59．39±4．55）％、（74.36±6．78）％、（86．43±8．43）％;3群细胞的成瘤能力和侵袭能力都存在显著统计学差异（P值〈0．05）：流式细胞分选技术分选后细胞〉无血清悬浮培养联合化疗药物处理细胞〉单纯无血清悬浮培养细胞。结论流式细胞分选技术富集癌干细胞的能力强于单纯无血清悬浮培养和无血清悬浮培养联合化疗药物,无血清悬浮培养联合化疗药物又强于单纯无血清悬浮培养。