Production of CA125 in cell lines derived from human ovarian carcinoma: in relation to the cell cycle

The association of the production of CA125 with the cell cycle was investigated in two cell lines derived from human ovarian cancer, one from a serous cystadenocarcinoma (HTOA) and the other from a mucinous cystadenocarcinoma (RMUG-s). HTOA and RMUG-s cells secreted CA125 at about 50 and 30U/ml/10(5) cell/24hr, respectively, in the logarithmic growth phase and at about 75 and 100U/ml/10(5) cell/24hr in the steady phase. Analysis by FCM revealed that cultures of both cell lines cultured for 7 days contained more cells in the G0/G1 phase and less cells in the S phase than those cultured for 3 days. The positive rate of immunologically stained DNA polymerase alpha was 31% in HTOA cells and 39% in RMUG-s cells after cultivation of the cells for 3 days. The addition of EGF at 0.01, 0.1 or 1.0nM did not affect the production of CA125 in HTOA or RMUG-s cells while the addition of NaBT at 1, 3 and 5mM raised production in both cell lines as the dose rose. With RMUG-s cells, the addition of EGF at 0.01nM to the culture media accelerated both logarithmic and steady phase growth without a significant change in the production of CA125. In contrast, the addition of NaBT at 1mM suppressed growth, but tended to increase the production of CA125 per cell. With the effect of EGF on the cell cycle of both cell lines, cells in the S phase increased by about 20% as compared with the control, 48 hours after its addition at 0.01nM. In contrast, after cultivation for 48 hours in the presence of 1mM NaBT, cells in the S phase were decreased while those in the G0/G1 phase increased. The results presented above suggested the possibility that some factors other than the cell cycle were involved in the production of CA125. There also is close correlation between cells in the G0/G1 phase and the production of CA125 in the culture of human ovarian cancer cells.