Reduction of tumor necrosis factor-alpha bioactivity by a human ovarian epithelial cancer cell line in vitro.
OBJECTIVE
Our purpose was to determine the ability of an ovarian epithelial carcinoma cell line, Caov-3, to alter the bioactivity of exogenously added tumor necrosis factor-alpha.


METHODS
Caov-3 cells were cultured for up to 6 days in Dulbecco's modified Eagle's medium containing 10% fetal calf serum. The control and tumor necrosis factor-alpha-treated cells were analyzed for proliferation, distribution throughout the cell cycle by flow cytometry, their ability to release bioactive tumor necrosis factor-alpha by L929 bioassay, and their ability to release immunoreactive tumor necrosis factor-alpha by a specific double sandwich enzyme-linked immunosorbent assay.


RESULTS
Tumor necrosis factor-alpha induced a dose- and time-dependent inhibition of cell proliferation accompanied by accumulation of cells in late S and G2/M phases of the cell cycle. Tumor necrosis factor-alpha bioactivity was undetectable in the media of control Caov-3 cell cultures, but these cells exhibited TNF-alpha messenger ribonucleic acid. After culture of the cells for 2 days in the presence of various doses of TNF-alpha (0.1, 1.0, 10, or 100 ng/ml), a significant decline (p < 0.01) in bioactivity was observed in all groups with the exception of 100 ng of TNF-alpha. Further declines in bioactivity were observed 2 and 4 days later. Addition of TNF-alpha to Caov-3 cells did not affect its immunoactivity, and Western blots of media revealed major bands of immunoactivity at approximately 17 kd, the expected molecular size of TNF-alpha.


CONCLUSIONS
These results indicate that Caov-3 ovarian carcinoma cells reduce the bioactivity of TNF-alpha, an important growth regulator, by a novel yet unknown mechanism to escape the modulatory effects of the normal immune response during cancer cell growth.
Sancho-Tello
M
M
Department of Physiology Obstetrics, University of Kansas Cancer Center, Kansas City 66160-7401, USA.
Marcinkiewicz
J L
JL
Justice
W M
WM
Kimler
B F
BF
Terranova
P F
PF
Hunter
V J
VJ
D000818:Animals; D015152:Blotting, Northern; D002277:Carcinoma; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D017077:Culture Media, Conditioned; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression; D006801:Humans; D007700:Kinetics; D007739:L Cells; D051379:Mice; D010051:Ovarian Neoplasms; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000494:pharmacology*
D017077:Culture Media, Conditioned; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha