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Ex Vivo Culture of Primary Human Fallopian Tube Epithelial Cells
Published on: May 9, 2011
Primary ovarian cancer cultures are resistant to Fas-mediated apoptosis
R L Baldwin1, H Tran, B Y Karlan
1Department of Obstetrics and Gynecology, The Burns and Allen Research Institute, Los Angeles, California, 90048, USA.
Objectives:
Fas, a primary mediator of cellular apoptosis, is expressed by the normal ovarian epithelium. We analyzed the levels of Fas and soluble Fas (sFas) expression in ovarian cancer tissue and determined the susceptibility of primary ovarian cancer cell (CSOC) cultures to Fas-mediated apoptosis.
Methods:
Fas mRNA levels were detected by RT-PCR, and Fas protein levels were determined by immunohistochemistry and Western blot analysis. Secreted sFas levels were measured by ELISA. Localization of Fas to the cell surface was demonstrated by flow cytometry. The effect of Fas on cell proliferation was measured by MTT assay.
Results:
Intense Fas staining was detected on the cell surface and in the cytoplasm of ovarian carcinoma specimens. We also found that mean levels of sFas, which can function as a Fas agonist, were significantly increased in 18 sera from cancer patients (0.98 ng/ml) compared to those of 8 healthy individuals (0.61 ng/ml, P = 0.004). Fas mRNA and protein were expressed in all primary ovarian cancer cell cultures. Despite abundant Fas expression, CSOC cultures were significantly less sensitive to Fas-mediated apoptosis (11.3%) than primary cultures of normal ovarian epithelial cells (HOSE) (50.0%) (P = 0.00001). The sFas level in CSOC-conditioned medium was minimal (0.07 ng/ml) and not significantly different from that of HOSE-conditioned medium (0. 09 ng/ml). The small amount of sFas secreted by CSOC does not likely account for the observed resistance to Fas-mediated apoptosis.
Conclusion:
Decreased sensitivity to Fas-mediated apoptosis could contribute to ovarian tumorigenesis through resistance to cytotoxic T lymphocyte-mediated cytotoxicity and may play a role in ovarian tumorigenesis.
Insights
Ovarian cancer cells show high Fas expression but reduced sensitivity to apoptosis. This resistance may contribute to tumor development by evading immune responses.
Area of Science:
- Oncology
- Immunology
- Cell Biology
Background:
- Fas is a key mediator of apoptosis and is present in normal ovarian epithelium.
- Understanding Fas expression and apoptosis sensitivity in ovarian cancer is crucial for therapeutic development.
Purpose of the Study:
- To analyze Fas and soluble Fas (sFas) expression in ovarian cancer.
- To determine the susceptibility of ovarian cancer cells to Fas-mediated apoptosis.
Main Methods:
- Fas mRNA and protein levels were assessed using RT-PCR, immunohistochemistry, and Western blot.
- Soluble Fas (sFas) levels were measured by ELISA.
- Apoptosis sensitivity was evaluated via MTT assay and flow cytometry.
Main Results:
- Ovarian carcinoma specimens exhibited intense Fas staining.
- Serum sFas levels were significantly higher in cancer patients than in healthy individuals.
- Ovarian cancer cell cultures showed abundant Fas expression but significantly reduced sensitivity to Fas-mediated apoptosis compared to normal ovarian cells.
Conclusions:
- Decreased sensitivity to Fas-mediated apoptosis in ovarian cancer cells may promote tumorigenesis.
- This resistance could be linked to evasion of cytotoxic T lymphocyte-mediated cell death.
- Fas signaling pathways warrant further investigation in ovarian cancer treatment strategies.
