技术资料

A series of chalcones (1-9) and pyrazoles (10-18) was prepared to investigate their potential activity as Angiotensin I-Converting Enzyme (ACE) inhibitors. Their structures were verified by elemental analysis,UV,IR,MS,(1)H NMR,(13)C NMR,and 2D NMR experiments. Among tested compounds,chalcone 7 exerted the highest activity with an IC(50) value of 0.219 mM,while the most potent pyrazole was 15 (IC(50) value of 0.213 mM). View Publication

Following activation through the TCR,CD4+ T cells can differentiate into three major subsets: Th1,Th2,and Th17 cells. IL-17-secreting Th17 cells play an important role in the pathogenesis of several autoimmune diseases and in immune responses to pathogens,but little is known about the regulation of apoptosis in Th17 cells. In this study,the sensitivity of in vitro-polarized Th1,Th2,and Th17 cells to Fas-mediated apoptosis was compared directly by different methods. The order of sensitivity of T cell subsets to Fas-mediated apoptosis is: Th1 textgreater Th17 textgreater Th2. The greater sensitivity of Th17 cells to Fas-mediated apoptosis compared with Th2 cells correlated with their higher expression of FasL and comparable expression of the antiapoptotic molecule FLIP. The decreased sensitivity of Th17 compared with Th1 cells correlated with the higher expression of FLIP by Th17 cells. Transgenic overexpression of FLIP in T cells protected all three subsets from Fas-mediated apoptosis. These findings provide new knowledge for understanding how survival of different subsets of T cells is regulated. View Publication

GCS-100 is a galectin-3 antagonist with an acceptable human safety profile that has been demonstrated to have an antimyeloma effect in the context of bortezomib resistance. In the present study,the mechanisms of action of GCS-100 are elucidated in myeloma cell lines and primary tumor cells. GCS-100 induced inhibition of proliferation,accumulation of cells in sub-G(1) and G(1) phases,and apoptosis with activation of both caspase-8 and -9 pathways. Dose- and time-dependent decreases in MCL-1 and BCL-X(L) levels also occurred,accompanied by a rapid induction of NOXA protein,whereas BCL-2,BAX,BAK,BIM,BAD,BID,and PUMA remained unchanged. The cell-cycle inhibitor p21(Cip1) was up-regulated by GCS-100,whereas the procycling proteins CYCLIN E2,CYCLIN D2,and CDK6 were all reduced. Reduction in signal transduction was associated with lower levels of activated IkappaBalpha,IkappaB kinase,and AKT as well as lack of IkappaBalpha and AKT activation after appropriate cytokine stimulation (insulin-like growth factor-1,tumor necrosis factor-alpha). Primary myeloma cells showed a direct reduction in proliferation and viability. These data demonstrate that the novel therapeutic molecule,GCS-100,is a potent modifier of myeloma cell biology targeting apoptosis,cell cycle,and intracellular signaling and has potential for myeloma therapy. View Publication

UNLABELLED: Human stem cells from adult sources have been shown to contribute to the regeneration of muscle,liver,heart,and vasculature. The mechanisms by which this is accomplished are,however,still not well understood. We tested the engraftment and regenerative potential of human umbilical cord blood-derived ALDH(hi)Lin(-),and ALDH(lo)Lin(-) cells following transplantation to NOD/SCID or NOD/SCID beta2m null mice with experimentally induced acute myocardial infarction. We used combined nanoparticle labeling and whole organ fluorescent imaging to detect human cells in multiple organs 48 hours post transplantation. Engraftment and regenerative effects of cell treatment were assessed four weeks post transplantation. We found that ALDH(hi)Lin(-) stem cells specifically located to the site of injury 48 hours post transplantation and engrafted the infarcted heart at higher frequencies than ALDH(lo)Lin(-) committed progenitor cells four weeks post transplantation. We found no donor derived cardiomyocytes and few endothelial cells of donor origin. Cell treatment was not associated with any detectable functional improvement at the four week endpoint. There was,however,a significant increase in vascular density in the central infarct zone of ALDH(hi)Lin(-) cell-treated mice,as compared to PBS and ALDH(lo)Lin(-) cell-treated mice. CONCLUSIONS: Our data indicate that adult human stem cells do not become a significant part of the regenerating tissue,but rapidly home to and persist only temporarily at the site of hypoxic injury to exert trophic effects on tissue repair thereby enhancing vascular recovery. View Publication

Lentiviruses are capable of infecting many cells irrespective of their cycling status,stably inserting DNA copies of the viral RNA genomes into host chromosomes. This property has led to the development of lentiviral vectors for high-efficiency gene transfer to a wide variety of cell types,from slowly proliferating hematopoietic stem cells to terminally differentiated neurons. Regardless of their advantage over gammaretroviral vectors,which can only introduce transgenes into target cells that are actively dividing,lentiviral vectors are still susceptible to chromosomal position effects that result in transgene silencing or variegated expression. In this chapter,various genetic regulatory elements are described that can be incorporated within lentiviral vector backbones to minimize the influences of neighboring chromatin on single-copy transgene expression. The modifications include utilization of strong internal enhancer-promoter sequences,addition of scaffold/matrix attachment regions,and flanking the transcriptional unit with chromatin domain insulators. Protocols are provided to evaluate the performance as well as the relative biosafety of lentiviral vectors containing these elements. View Publication

INTRODUCTION: Various synthetic bone-graft substitutes are used commercially as osteoconductive scaffolds in the treatment of bone defects and fractures. The role of bone-graft substitutes is changing from osteoconductive conduits for growth to an delivery system for biologic fracture treatments. Achieving optimal bone regeneration requires biologics (e.g. MSC) and using the correct scaffold incorporated into a local environment for bone regeneration. The need for an unlimited supply with high quality bone-graft substitutes continue to find alternatives for bone replacement surgery. MATERIALS AND METHODS: This in vitro study investigates cell seeding efficiency,metabolism,gene expression and growth behaviour of MSC sown on six commercially clinical available bone-graft substitutes in order to define their biological properties: synthetic silicate-substituted porous hydroxyapatite (Actifuse ABX),synthetic alpha-TCP (Biobase),synthetic beta-TCP (Vitoss),synthetic beta-TCP (Chronos),processed human cancellous allograft (Tutoplast) and processed bovines hydroxyapatite ceramic (Cerabone). 250,000 MSC derived from human bone marrow (n=4) were seeded onto the scaffolds,respectively. On days 2,6 and 10 the adherence of MSC (fluorescence microscopy) and cellular activity (MTT assay) were analysed. Osteogenic gene expression (cbfa-1) was analysed by RT-PCR and scanning electron microscopy was performed. RESULTS: The highest number of adhering cells was found on Tutoplast (e.g. day 6: 110.0+/-24.0 cells/microscopic field; ptextless0.05) followed by Chronos (47.5+/-19.5,ptextless0.05),Actifuse ABX (19.1+/-4.4),Biobase (15.7+/-9.9),Vitoss (8.8+/-8.7) and Cerabone (8.1+/-2.2). MSC seeded onto Tutoplast showed highest metabolic activity and gene expression of cbfa-1. These data are confirmed by scanning electron microscopy. The cell shapes varied from round-shaped cells to wide spread cells and cell clusters,depending on the bone-graft substitutes. Processed human cancellous allograft is a well-structured and biocompatible scaffold for ingrowing MSC in vitro. Of all other synthetical scaffolds,beta-tricalcium phosphate (Chronos) have shown the best growth behaviour for MSC. DISCUSSION: Our results indicate that various bone-graft substitutes influence cell seeding efficiency,metabolic activity and growth behaviour of MSC in different manners. We detected a high variety of cellular integration of MSC in vitro,which may be important for bony integration in the clinical setting. View Publication

Transforming growth factor (TGF)-beta superfamily proteins play a key role in the regulation of human embryonic stem cells (hESCs). Those of the TGFbeta/activin/nodal branch seem to support self-renewal and pluripotency,whereas those of the bone morphogenic protein (BMP) branch induce differentiation. In contrast to this generalization,we found that hESC remained undifferentiated after knockdown of SMAD4 with inducible short hairpin RNA interference,although the knockdown inhibited TGFbeta signaling and rendered the cells nonresponsive to BMP-induced differentiation. Moreover,the rapid differentiation of hESC after pharmacological inhibition of TGFbeta/activin/nodal receptor signaling was restricted after SMAD4 knockdown. These results suggest that TGFbeta/activin/nodal signaling supports the undifferentiated phenotype of hESC by suppressing BMP activity. During long-term culture,SMAD4 knockdown cell populations became less stable and more permissive to neural induction,a situation that was rescued by re-establishment of SMAD4 expression. These results suggest that SMAD4 is not required for maintenance of the undifferentiated state of hESC,but rather to stabilize that state. View Publication

The study of human erythropoiesis in health and disease requires a robust culture system that consistently and reliably generates large numbers of immature erythroblasts that can be induced to differentiate synchronously. We describe a culture method modified from Leberbauer et al. (2005) and obtain a homogenous population of erythroblasts from peripheral blood mononuclear cells (PBMC) without prior purification of CD34(+) cells. This pure population of immature erythroblasts can be expanded to obtain 4x10(8) erythroblasts from 1x10(8) PBMC after 13-14 days in culture. Upon synchronized differentiation,high levels of enucleation (80-90%) and low levels of cell death (textless10%) are achieved. We compared the yield of erythroblasts obtained from PBMC,CD34(+) cells or PBMC depleted of CD34(+) cells and show that CD34(-) cells represent the most significant early erythroid progenitor population. This culture system may be particularly useful for investigating the pathophysiology of anemic patients where only small blood volumes are available. View Publication

Metabolic studies of human embryonic stem cells (hESCs) can provide important information for stem cell bioprocessing. To this end,we have examined growth and metabolism of hESCs in both traditional 2-dimensional (2D) colony cultures and 3-dimensional microcarrier cultures using a conditioned medium and 3 serum-free media. The 2D colony cultures plateaued at cell densities of 1.1-1.5 × 10�?� cells/mL at day 6 due to surface limitation. Microcarrier cultures achieved 1.5-2 × 10�?� cells/mL on days 8-10 before reaching a plateau; this growth arrest was not due to surface limitation,but probably due to metabolic limitations. Metabolic analysis of the cultures showed that amino acids (including glutamine) and glucose are in excess and are not limiting cell growth; on the other hand,the high levels of waste products (25 mM lactate and 0.8 mM ammonium) and low pH (6.6) obtained at the last stages of cell propagation could be the causes for growth arrest. hESCs cultured in media supplemented with lactate (up to 28 mM) showed reduced cell growth,whereas ammonium (up to 5 mM) had no effect. Lactate and,to a lesser extent,ammonia affected pluripotency as reflected by the decreasing population of cells expressing pluripotent marker TRA-1-60. Feeding hESC cultures with low concentrations of glucose resulted in lower lactate levels (∼10%) and a higher pH level of 6.7,which leads to a 40% increase in cell density. We conclude that the high lactate levels and the low pH during the last stages of high-density hESC culture may limit cell growth and affect pluripotency. To overcome this limitation,a controlled feed of low levels of glucose and online control of pH can be used. View Publication

PURPOSE: The existence of cancer stem cells (CSCs) in breast cancer has profound implications for cancer prevention. In this study,we evaluated sulforaphane,a natural compound derived from broccoli/broccoli sprouts,for its efficacy to inhibit breast CSCs and its potential mechanism. EXPERIMENTAL DESIGN: Aldefluor assay and mammosphere formation assay were used to evaluate the effect of sulforaphane on breast CSCs in vitro. A nonobese diabetic/severe combined immunodeficient xenograft model was used to determine whether sulforaphane could target breast CSCs in vivo,as assessed by Aldefluor assay,and tumor growth upon cell reimplantation in secondary mice. The potential mechanism was investigated using Western blotting analysis and beta-catenin reporter assay. RESULTS: Sulforaphane (1-5 micromol/L) decreased aldehyde dehydrogenase-positive cell population by 65% to 80% in human breast cancer cells (P textless 0.01) and reduced the size and number of primary mammospheres by 8- to 125-fold and 45% to 75% (P textless 0.01),respectively. Daily injection with 50 mg/kg sulforaphane for 2 weeks reduced aldehyde dehydrogenase-positive cells by textgreater50% in nonobese diabetic/severe combined immunodeficient xenograft tumors (P = 0.003). Sulforaphane eliminated breast CSCs in vivo,thereby abrogating tumor growth after the reimplantation of primary tumor cells into the secondary mice (P textless 0.01). Western blotting analysis and beta-catenin reporter assay showed that sulforaphane downregulated the Wnt/beta-catenin self-renewal pathway. CONCLUSIONS: Sulforaphane inhibits breast CSCs and downregulates the Wnt/beta-catenin self-renewal pathway. These findings support the use of sulforaphane for the chemoprevention of breast cancer stem cells and warrant further clinical evaluation. View Publication

It has been shown that genetic inhibition of p53 leads to enhanced proliferation of hematopoietic stem cells (HSCs). This could,in theory,contribute to the increased frequency of tumor development observed in p53-deficient mice and humans. In our previous work,we identified chemical p53 inhibitors (PFTs) that suppress the transactivation function of p53 and protect cultured cells and mice from death induced by gamma irradiation (IR). Here we found that when applied to bone marrow cells in vitro or injected into mice,PFTb impeded IR-induced reduction of hematopoietic stem cell (HSC) and hematopoietic progenitor cell (HPC) population sizes. In addition,we showed that PFTb stimulated HSC and HPC proliferation in the absence of IR in vitro and in vivo and mobilized HSCs to the peripheral blood. Importantly,however,PFTb treatment did not affect the timing or frequency of tumor development in irradiated p53 heterozygous mice used as a model for determination of carcinogenicity. Thus,although PFTb administration led to increased numbers of HSCs and HPCs,it was not carcinogenic in mice. These findings suggest that chemical p53 inhibitors may be clinically useful as safe and effective stimulators of hematopoiesis. View Publication

First developed for hematologic disorders,the concept of cancer stem cells (CSCs) was expanded to solid tumors,including colorectal cancer (CRC). The traditional model of colon carcinogenesis includes several steps that occur via mutational activation of oncogenes and inactivation of tumor suppressor genes. Intestinal epithelial cells exist for a shorter amount of time than that required to accumulate tumor-inducing genetic changes,so researchers have investigated the concept that CRC arises from the long-lived stem cells,rather than from the differentiated epithelial cells. Colon CSCs were originally identified through the expression of the CD133 glycoprotein using an antibody directed to its epitope AC133. It is not clear if CD133 is a marker of colon CSCs-other cell surface markers,such as epithelial-specific antigen,CD44,CD166,Musashi-1,CD29,CD24,leucine-rich repeat-containing G-protein-coupled receptor 5,and aldehyde dehydrogenase 1,have been proposed. In addition to initiating and sustaining tumor growth,CSCs are believed to mediate cancer relapse after chemotherapy. How can we identify and analyze colon CSCs and what agents are being designed to kill this chemotherapy-refractory population? View Publication