| BackgroundEpithelial ovarian carcinoma is the first lethal cause in gynecological malignancies in women. One of the reasons is that most of the patients with ovarian carcinoma present advanced-stage with wide-spread of cancer cells in the peritoneal cavity at the first diagnosis. The host's immune defect is regarded as an important cause of the metastasis of ovarian carcinoma. It's well known that the function and quantities of immune system cells in peritoneal cavity were significantly decreased, including T cells, NKs and dendritic cells.Dendritic cell (DC) is the most powerful antigen presenting cells in immune system. DC plays central roles in immuno-response by initiating immune reactions against a wide variety of antigens and activating T cells. A great number of evidences have demonstrated that DC possesses the capacity to induce tumor specific immune responses. The insensitivity of established tumors to immunesystem cells is likely due to some factors existing in the tumor microenvironment that are inimical to the optimal induction of an antitumor immune response. It has been shown that tumor cells can product some factors to inhibit DC quantities and function by blocking its differentiation into potent immunocompetent cells. Recent studies also revealed that tumor cells can eliminate DC by inducing its apoptosis.The basic apoptotic pathway includes death receptor pathway, mitochondrial pathway and endoplasmic reticulum stress pathway. Tumor cells expressing Fas L may protect themselves from immune surveillance by inducing Fas-mediated apoptosis in immune cells. However, this theory has recently been challenged by in vivo data that Fas L may actually promote tumor rejection rather than its survival. Therefore, It is postulated that tumor cells can secrete soluble factor(s) to induce DC apoptosis, but the mechanism is still unclear.In the study, apoptotic indices of DC induced by ovarian carcinoma cell lines (3AO,SKOV3, CA0V3) with the different concentrations and different effect-times were detected by flow cytometry with assessments of the phosphatidylserine/propidium iodide stain kit (Annexin V-FITC) and the mitochondrial transmembrane potential detection kit (MitoCapture). The aim of the study is to identify whether ovarian carcinoma cells can secrete factor(s) to induce DC apoptosis and to find a possible mechanism of tumor-induced DC apoptotic procedure.Materials and MethodsMature DC derived from CD34~+ hematopoietic stem cells were selected for the study. DC apoptosis was induced by the supernatant of three epithelial ovarian carcinoma cell Lines (3AO, SK0V3 and CA0V3) with different concentrations (0,60,120,180,240μL) and different effect-times(0,12,24,48,72hour).The apoptotic index of DC was detected and quantificated by flow cytometry with assessments of the phosphatidylserine/ propidium iodide detection kit (Annexin V-FITC) and the mitochondrial transmembrane potential detection kit (MitoCapture).Oneway ANOVA was used for statistical analysis. ALL data were managed with SPSS 12.0 for windows.Results1. A total of 1000ml supernatants of ovarian carcinoma cell lines without fetal bovine serum were collected in six months, then concentrated into 10ml by dialysis and vacuum freeze-dry.2. DC apoptosis occurred during induction of the supernatant of three ovarian carcinoma cell lines, and the apoptotic indices were increased when the supernatant concentration was increased.3. The early apoptosis of DC was detected in 12hours of the supernatant effect of three cell lines, and the early apoptotic indices were increased when the effect-time was prolonged. The Late apoptosis of DC was detected in 12hours(SKOV3), 24hours(3AO), and 72hours(CAOV3) of the supernatant effect.4. There were no differences of apoptotic indices between phosphatidylserine and mitochondrial transmembrane potential assessment in 3AO and SKOV3, but apoptotic indices were higher with the phosphatidylserine assessment than those with the mitochondrial transmembrane potential assessment in CAOV3.Conclusions1. The super...
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