Thus, some glioma cell lines call for the co exposure to CD ligand and inhibitors of RNA and protein synthesis for sensitization to apoptosis, indicating the constitutive or induced expression of labile cytoprotective proteins which inhibit apoptosis. The signal transduction events while in CD mediated apoptosis of human glioma cells have not been studied in detail. Here we examine the role of AA metabolism in CD ligand induced apoptosis of those cells. AA release may very well be of particular interest considering the fact that dexamethasone, an inhibitor of PLA, attenuates CD mediated glioma cell apoptosis . CD mediated apoptosis of human malignant glioma cells is connected to the release of AA The position of AA metabolic process in CD mediated apoptosis of human malignant glioma cells was examined in 3 glioma cell lines with numerous patterns of sensitivity to CD ligand . LN expresses moderate levels of CD and it is tremendously sensitive to CD ligand. LN exhibits high expression of CD but is rather resistant to CD ligand unless of course coexposed to inhibitors of RNA and protein synthesis.
LN is resistant to CD ligand because of tiny CD expression on the cell surface. LN cells engineered to express large amounts of CD get sensitivity to CD mediated apoptosis . Fig. illustrates that CD ligand induced apoptosis evolves more quickly in LN than in LN cells but that co publicity to CHX is needed for apoptosis in LN cells. To investigate a CD ligand mediated AA release, glioma cells labeled with AA have been exposed to CD ligand from the absence or presence specific Src inhibitor of CHX. Time dependent modifications from the levels of H labeled compounds had been monitored from the cell culture medium at the same time as in cytosolic, nuclear and particulate cell fractions. There was an increase in AA in the cell culture medium peaking at h following exposure to CD ligand correlating using the induction of cytotoxicity : CD ligand induced AA release in LN cells ; CHX cotreatment elevated AA release by CD ligandtreated LN cells ; while no AA was launched from CD ligand treated LN neo cells, CD transfected LN cells, that are sensitized to CD mediated apoptosis , have been induced to release AA by CD ligand .
The differential quantification of radioactivity in supernatant, nucleus, cytoplasm and particulate fractions unveiled that radioactive AA was released in the particulate fraction . To confirm that AA release was not an unspecific consequence of cell death, we performed parallel experiments to stick to the time programs for AA release, DNA fragmentation and trypan blue dye exclusion. We observed AA release in LN cells about PS-341 h just before CD ligand mediated apoptosis was detected by crystal violet staining and trypan blue uptake . In LN cells, AA release precedes both DNA fragmentation and trypan blue uptake .