搜索结果: 'methocult media formulations for human hematopoietic cells serum containing'

The major goal of researchers and oncologists is to develop promising ground for novel therapeutic strategies to prevent recurrence or relapse of cancer. Recent evidences suggest that a subset of cells called cancer stem cells (CSCs) are present within the tumor mass which possess tumorigenic capacity and may be responsible for propagation,relapse,and metastatic dissemination. These cells have certain stem cell-like properties,e.g. quiescence,selfrenewal,asymmetric division,and multidrug resistance which allow them to drive tumor growth and evade conventional therapies. A number of markers and assays have been designed to isolate and characterize the CSC population from the bulk tumor. The objective now is to selectively target the CSCs in order to eliminate the tumor from root,overcoming the emergence of clones capable of evading traditional therapy. This approach may help in increasing the overall disease-free survival in some cancers. View Publication

The coding region determinant-binding protein/insulin-like growth factor II mRNA-binding protein (CRD-BP/IMP1) is an RNA-binding protein specifically recognizing c-myc,leader 3' IGF-II and tau mRNAs,and the H19 RNA. CRD-BP/IMP1 is predominantly expressed in embryonal tissues but is de novo activated and/or overexpressed in various human neoplasias. To address the question of whether CRD-BP/IMP1 expression characterizes certain cell types displaying distinct proliferation and/or differentiation properties (i.e. stem cells),we isolated cell subpopulations from human bone marrow,mobilized peripheral blood,and cord blood,all sources known to contain stem cells,and monitored for its expression. CRD-BP/IMP1 was detected only in cord blood-derived CD34(+) stem cells and not in any other cell type of either adult or cord blood origin. Adult BM CD34(+) cells cultured in the presence of 5'-azacytidine expressed de novo CRD-BP/IMP1,suggesting that epigenetic modifications may be responsible for its silencing in adult non-expressing cells. Furthermore,by applying the short interfering RNA methodology in MCF-7 cells,we observed,subsequent to knocking down CRD-BP/IMP1,decreased c-myc expression,increased IGF-II mRNA levels,and reduced cell proliferation rates. These data 1) suggest a normal role for CRD-BP/IMP1 in pluripotent stem cells with high renewal capacity,like the CB CD34(+) cells,2) indicate that altered methylation may directly or indirectly affect its expression in adult cells,3) imply that its de novo activation in cancer cells may affect the expression of c-Myc and insulin-like growth factor II,and 4) indicate that the inhibition of CRD-BP/IMP1 expression might affect cancer cell proliferation. View Publication

The purpose of this study is to characterize the microRNA (miRNA) expression profiles of induced pluripotent stem (iPS) cells and retinal pigment epithelium (RPE) derived from induced pluripotent stem cells (iPS-RPE). MiRNAs have been demonstrated to play critical roles in both maintaining pluripotency and facilitating differentiation. Gene expression networks accountable for maintenance and induction of pluripotency are linked and share components with those networks implicated in oncogenesis. Therefore,we hypothesize that miRNA expression profiling will distinguish iPS cells from their iPS-RPE progeny. To identify and analyze differentially expressed miRNAs,RPE was derived from iPS using a spontaneous differentiation method. MiRNA microarray analysis identified 155 probes that were statistically differentially expressed between iPS and iPS-RPE cells. Up-regulated miRNAs including miR-181c and miR-129-5p may play a role in promoting differentiation,while down-regulated miRNAs such as miR-367,miR-18b,and miR-20b are implicated in cell proliferation. Subsequent miRNA-target and network analysis revealed that these miRNAs are involved in cellular development,cell cycle progression,cell death,and survival. A systematic interrogation of temporal and spatial expression of iPS-RPE miRNAs and their associated target mRNAs will provide new insights into the molecular mechanisms of carcinogenesis,eye differentiation and development. View Publication

Individual variation in fetal hemoglobin (HbF,alpha(2)gamma(2)) response underlies the remarkable diversity in phenotypic severity of sickle cell disease and beta thalassemia. HbF levels and HbF-associated quantitative traits (e.g.,F cell levels) are highly heritable. We have previously mapped a major quantitative trait locus (QTL) controlling F cell levels in an extended Asian-Indian kindred with beta thalassemia to a 1.5-Mb interval on chromosome 6q23,but the causative gene(s) are not known. The QTL encompasses several genes including HBS1L,a member of the GTP-binding protein family that is expressed in erythroid progenitor cells. In this high-resolution association study,we have identified multiple genetic variants within and 5' to HBS1L at 6q23 that are strongly associated with F cell levels in families of Northern European ancestry (P = 10(-75)). The region accounts for 17.6% of the F cell variance in northern Europeans. Although mRNA levels of HBS1L and MYB in erythroid precursors grown in vitro are positively correlated,only HBS1L expression correlates with high F cell alleles. The results support a key role for the HBS1L-related genetic variants in HbF control and illustrate the biological complexity of the mechanism of 6q QTL as a modifier of fetal hemoglobin levels in the beta hemoglobinopathies. View Publication

Elotuzumab is a monoclonal antibody in development for multiple myeloma (MM) that targets CS1,a cell surface glycoprotein expressed on MM cells. In preclinical models,elotuzumab exerts anti-MM efficacy via natural killer (NK)-cell-mediated antibody-dependent cellular cytotoxicity (ADCC). CS1 is also expressed at lower levels on NK cells where it acts as an activating receptor. We hypothesized that elotuzumab may have additional mechanisms of action via ligation of CS1 on NK cells that complement ADCC activity. Herein,we show that elotuzumab appears to induce activation of NK cells by binding to NK cell CS1 which promotes cytotoxicity against CS1(+) MM cells but not against autologous CS1(+) NK cells. Elotuzumab may also promote CS1-CS1 interactions between NK cells and CS1(+) target cells to enhance cytotoxicity in a manner independent of ADCC. NK cell activation appears dependent on differential expression of the signaling intermediary EAT-2 which is present in NK cells but absent in primary,human MM cells. Taken together,these data suggest elotuzumab may enhance NK cell function directly and confer anti-MM efficacy by means beyond ADCC alone. View Publication

As a critical tumor suppressor,p53 is inactivated in human cancer cells by somatic gene mutation or disruption of pathways required for its activation. Therefore,it is critical to elucidate the mechanism underlying p53 activation after genotoxic and cellular stresses. Accumulating evidence has indicated the importance of posttranslational modifications such as acetylation in regulating p53 stability and activity. However,the physiological roles of the eight identified acetylation events in regulating p53 responses remain to be fully understood. By employing homologous recombination,we introduced various combinations of missense mutations (lysine to arginine) into eight acetylation sites of the endogenous p53 gene in human embryonic stem cells (hESCs). By determining the p53 responses to DNA damage in the p53 knock-in mutant hESCs and their derivatives,we demonstrate physiological importance of the acetylation events within the core domain (K120 and K164) and at the C-terminus (K370/372/373/381/382/386) in regulating human p53 responses to DNA damage. View Publication

Under standard culture conditions,tumor cells are exposed to 20% O(2),whereas the mean tumor oxygen levels within the tumor are much lower. We demonstrate,using low-passaged human tumor cell cultures established from glioma,that a reduction in the oxygen level in these cell cultures dramatically increases the percentage of CD133 expressing cells. View Publication

Mature mammary epithelial cells are generated from undifferentiated precursors through a hierarchical process,but the molecular mechanisms involved,particularly in the human mammary gland,are poorly understood. To address this issue,we isolated highly purified subpopulations of primitive bipotent and committed luminal progenitor cells as well as mature luminal and myoepithelial cells from normal human mammary tissue and compared their transcriptomes obtained using three different methods. Elements unique to each subset of mammary cells were identified,and changes that accompany their differentiation in vivo were shown to be recapitulated in vitro. These include a stage-specific change in NOTCH pathway gene expression during the commitment of bipotent progenitors to the luminal lineage. Functional studies further showed NOTCH3 signaling to be critical for this differentiation event to occur in vitro. Taken together,these findings provide an initial foundation for future delineation of mechanisms that perturb primitive human mammary cell growth and differentiation. View Publication

An in vivo transplantation system has been used to evaluate the developmental capacities of specific mouse mammary epithelial cell populations. Specifically,mouse mammary epithelial cells with distinctly limited developmental potentials have been identified using this procedure. Two distinct epithelial cell progenitors have been identified by experiments designed to determine whether basal lobular and ductal phenotypes could develop independently under conditions imposed by a limiting dilution. The prediction that these separate epithelial progenitors must exist was based upon the results from transplantation experiments carried out in epithelium-divested mammary fat pads of syngeneic mice with mammary epithelium from two different transgenic mouse models. The results presented here demonstrate the following points: 1) lobular,i.e. secretory,progenitor cells are present as distinct entities among the mammary epithelial cells found in immature virgin female mice; 2) similarly,ductal epithelial progenitors are present within the same population; 3) lobular progenitors are present in greater numbers,although both cell populations are extremely small; 4) as expected,some inocula produce outgrowths with simultaneous development of both lobular and ductal phenotypes--it is not known whether this indicates cooperative interaction between the two epithelial progenitors or signals the presence of a third progenitor type capable of producing both ductular and lobular committed daughters; 5) these findings have important consequences in the design of experiments aimed at testing the effects of known and putative mammary oncogenes and tumor suppressor genes,using techniques which include cellular transformation in vitro followed by in vivo cultivation and evaluation. View Publication