Cox 2 Inhibitor

Therefore, approximately half of the no take human tumor cell lines available through ATCC are truly nontumorigenic, and half undergo a dormancy period before they spontaneously switch to the angiogenic phenotype.These clones were than expanded in vitro and the resulting cell populations were then tested for tumor cell proliferation in vitro.The single cell clones with the highest and lowest proliferation rates were selected and tested in vivo for their angiogenic potential.In contrast, the clone with the lowest in vitro proliferation remained microscopic in size for approximately days.After this dormancy period, spontaneous tumors formed and became angiogenic.Strategies for isolation of nonangiogenic and angiogenic human tumor cell populations.Stable transfection of these cell lines induced loss of dormancy and provided supporting evidence that escape from the angiogenic phenotype is controlled, in part, by a switch to the angiogenic phenotype.In this animal model, the angiogenic tumor cells were produced by genetic manipulation of otherwise dormant human tumor cells.Human tumor cell lines were selected from ATCC based on their nontumorigenic in immunocompromised mice phenotype.These were expanded in vitro, and their in vivo tumorigenic potential was assessed through the duration of the life of SCID mice.Spontaneous tumors began to form at the site of inoculation after a dormancy period which varied in length. Stable cell lines were established from representative spontaneous tumors.When reinoculated into animals, these cell lines formed large angiogenic tumors within a month in of the animals.This result was confirmed in all cancer types tested to date. Using this approach, angiogenic and nonangiogenic tumor cell populations were isolated from various human cancer types.For example, a subpopulation of tumor cells that overexpress thrombospondin, but secrete low levels of VEGF and bFGF would be expected to exhibit the dormant phenotype in vivo.The development of in vitro assays which can segregate the nonangiogenic and angiogenic tumor cell populations is currently under investigation.In summary, in vivo separation of nonangiogenic and angiogenic human tumor cell populations can be achieved by inoculating a large number of tumor cells into immunocompromised mice.The origin of these human tumor cells can be either a surgical specimen or an established cell line from ATCC. If a surgical specimen is used, part of the tissue can be homogenized and the other portion can be cut into tumor tissue cubes of known size and implanted into the subcutaneous space in mice.Tumor tissue implantation is preferred because the original stromal architecture of the tumor is preserved as much as possible without the mechanical or enzymatic damage introduced by the homogenization process.When tumors are well established, a stable cell line can be created under tissue culture conditions.In some instances tumor cells that had grown in vivo would not proliferate in vitro but remained subconfluent for Citric acid months.Genetic manipulation of these cells is an option, but is not advisable as it is not known how this step in the process would alter their in vivo behavior.It is imperative that the established cell line is confirmed to consist of the desired tumor cells, rather than stromal contaminants.A panel of antibodies specific to the cancer type can be used to identify the proportion of tumor cells in culture using flow cytometry, fixed cells grown on cover slips, or histology on cell Rebeprazole sodium pellets.

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