Cell culture

About: Cell culture is a research topic. Over the lifetime, 133361 publications have been published within this topic receiving 5364150 citations. The topic is also known as: cell culture techniques.

Biochemical characterization of a gamma interferon-inducible cytokine (IP-10).

Abstract: An IFN-gamma-inducible protein, IP-10, has previously been described to belong to a gene family of chemotactic and mitogenic proteins, associated with inflammation and proliferation. Biochemical characterization of this predicted protein has been pursued through the development of polyclonal monospecific antisera to recombinant protein and synthetic peptides. These reagents establish that the IP-10 protein is secreted from a variety of cells (endothelial, monocyte, fibroblast, and keratinocyte) in response to IFN-gamma. Posttranslational processing occurs in the biosynthesis of this protein, resulting in a 6-7-kD species, which may reflect COOH-terminal cleavage. Pulse-chase studies indicate that this processing is a rapid event in the primary cell lines studied, completed in the 30-min labeling period. A model is presented for the processing and secondary structure of this protein. In an accompanying study, Kaplan, et al. using these antisera, demonstrate that the IP-10 protein is associated, in vivo, with a delayed-type hypersensitivity response.

Brca1 breast tumors contain distinct CD44+/CD24- and CD133+ cells with cancer stem cell characteristics

Abstract: Whether cancer stem cells occur in BRCA1-associated breast cancer and contribute to therapeutic response is not known. We generated and characterized 16 cell lines from five distinct Brca1deficient mouse mammary tumors with respect to their cancer stem cell characteristics. All cell lines derived from one tumor included increased numbers of CD44+/CD24- cells, which were previously identified as human breast cancer stem cells. All cell lines derived from another mammary tumor exhibited low levels of CD44+/CD24- cells, but they harbored 2% to 5.9% CD133+ cells, which were previously associated with cancer stem cells in other human and murine tumors. When plated in the absence of attachment without presorting, only those cell lines that were enriched in either stem cell marker formed spheroids, which were further enriched in cells expressing the respective cancer stem cell marker. In contrast, cells sorted for CD44+/CD24- or CD133+ markers lost their stem cell phenotype when cultured in monolayers. As few as 50 to 100 CD44+/CD24- or CD133+ sorted cells rapidly formed tumors in nonobese diabetic/severe combined immunodeficient mice, whereas 50-fold to 100-fold higher numbers of parental or stem cell depleted cells were required to form few, slow-growing tumors. Expression of stem cell associated genes, including Oct4, Notch1, Aldh1, Fgfr1, and Sox1, was increased in CD44+/CD24- and CD133+ cells. In addition, cells sorted for cancer stem cell markers and spheroid-forming cells were significantly more resistant to DNA-damaging drugs than were parental or stem cell depleted populations, and they were sensitized to the drugs by the heat shock protein-90 inhibitor 17-DMAG (17-dimethylaminoethylamino-17-demethoxygeldanamycin hydrochloride). Brca1-deficient mouse mammary tumors harbor heterogeneous cancer stem cell populations, and CD44+/CD24- cells represent a population that correlates with human breast cancer stem cells.

IL-6 inhibits lipopolysaccharide-induced tumor necrosis factor production in cultured human monocytes, U937 cells, and in mice.

Abstract: Incubation of the human U937 histiocytic lymphoma cell line with granulocyte-macrophage colony stimulating factor (GM-CSF) rendered the cells responsive to induction of TNF by LPS. Treatment with IL-6 reduced TNF production in GM-CSF-primed U937 cells. The inhibitory effect was most pronounced (approximately equal to 80%) when IL-6 was added either along with GM-CSF or within the first 3 h of GM-CSF treatment. Both GM-CSF or IL-6 inhibited [3H]TdR uptake in U937 cells, and simultaneous treatment with GM-CSF and IL-6 resulted in an additive inhibitory effect on cell proliferation. However, the inhibition of TNF production could not be explained by the inhibitory effect of IL-6 on cell growth, nor was it due to a reduction in cell viability. An inhibition of TNF production by IL-6 was also demonstrated in cultured human peripheral blood monocytes. Treatment with IL-6 also resulted in a dose-dependent reduction of the 17-kDa TNF band revealed by SDS-PAGE after labeling monocytes with [35S]cysteine and immunoprecipitation with anti-TNF mAb. In addition, treatment with IL-6 resulted in a reduction of monocyte in vitro cytotoxicity for tumor target cells. Finally, in mice sensitized by the administration of Bacillus Calmette-Guerin, the injection of IL-6 significantly reduced the levels of TNF found in the serum upon challenge with LPS. Inasmuch as TNF is known to be an inducer of IL-6, the inhibitory action of IL-6 on TNF production may represent the negative arm of a regulatory circuit. The inhibitory action of IL-6 on TNF production is consistent with a predominantly antiinflammatory role of IL-6 in the intact organism.

Nerve growth factor receptors on human melanoma cells in culture

Abstract: Purified mouse nerve growth factor (NGF)radiolabeled with 125I was tested for its ability to bind to a variety of different cultured cells NGF binds readily to human and hamster melanoma cells but does not bind to many other cell lines The three cell lines with the highest number of NGF receptors were derived from metastatic melanomas One of these lines, A875, was studied in detail and was shown to have approximately 7x10(5) NGF receptors per cell with an association constant of 10x10(9) liters/mole The use of these cells in competition binding assays permits the detection of 025 ng of NGF in various biologic fluids NGF can be shown to increase the survival, but not the division, of melanoma cells maintained in medium depleted of serum growth factors This effect of NGF as a specific "survival factor" appears analogous to its effect on cultured sympathetic ganglion cells and on other cells derived from the neural crest