[Study of effect of mifepristone on apoptosis of human ovarian cancer cell line 3AO].

OBJECTIVE

To investigate the effect of mifepristone on the activity of proliferation and the apoptosis, the expression of estrogen receptor (ER), progesterone receptor (PR) protein and morphology changes of human ovarian carcinoma cell line 3AO and SKOV3 in vitro.

METHODS

The proliferative activity of 3AO and SKOV3, which were cultured in vitro, was measured by tetrazolium-based colorimetric assay (MTT assay). Flow cytormetry (FCM) was used to measure the expressive rate of ER, PR, p53 protein, bcl-2 protein, cell apoptotic rate and cell proliferative cycle of 3AO cells, which were cultured with different concentration and duration of mifepristone. The morphologic and ultrastructure changes of apoptotic 3AO cells was observed by the light and electron microscopy.

RESULTS

Mifepristone inhibited significantly the proliferation of 3AO cells in dose-time dependent manner in vitro. The inhibitory rate of 3AO cells growth, which were cultured with different concentration of mifepristone (5, 10, 20, 40, 80 micro mol/L) and duration (24, 48, 72 h) was from 1.7% to 75.0% (P < 0.01), but the proliferation activity of SKOV3 cells in vitro had not significant changes (P > 0.05). 3AO cells apoptosis activity appeared the positive correlation with the dose of mifepristone and cultured duration (P < 0.01). Mifepristone blocked 3AO cells proliferative cycle at the G(0)-G(1) stage, decreased the cell radio of S stage. Mifepristone induced the apoptosis of 3AO cells in vitro. The light and electron microscopy demonstrated that 3AO cells cultured with mifepristone appeared typical morphological characteristics of apoptosis including the compaction and margination of the chromosomes, nuclear fragments and formation of apoptotic bodies. Mifepristone up-regulated significantly the expression of p53 protein, but down-regulated the expression of bcl-2 protein (P < 0.01). The expressive rates of p53 and bcl-2 proteins were (54.8 +/- 4.0)% and (10.1 +/- 1.2)%, respectively, when 3AO cells was cultured with mifepristone of 10 micro mol/L for 24 h. Compared with the expression rates of control group (27.1 +/- 3.3)% and (17.6 +/- 1.0)%, the difference was significant (P < 0.01). The expressive rate of PR protein of 3AO cells cultured with mifepristone of 10 micro mol/L for 48 h was (12.7 +/- 1.4)%, which was decreased compared with the expressive rate of control group (44.9 +/- 1.4)% (P < 0.01).

CONCLUSIONS

Mifepristone inhibited significantly the proliferation and induced the cell apoptosis of cell line 3AO in dose-time dependent manner in vitro. The anti-tumor effect was related to down-regulation the expression of PR protein and bcl-2 protein, and to up-regulation the expression of p53 protein of 3AO cells.