Effect of 5-FU on expression of Bmi-1, Sca-1 and Oct-4 in human breast cancer cell line MDA-MB-468 / 临床与实验病理学杂志

ABSTRACT

Purpose To explore the relation between the expression of Bmi-1 and cancer stem cells and its relation to chemotherapy re-sistance in breast cancer. Methods MTT method was applied to detect the inhibition effect on proliferation of different concentrations (0. 01, 0. 1, 1, 10 μg/ml) of 5-Fluorouracil (5-FU) to MDA-MB-468 cells with 48 and 72 hours culture, a curve of proliferation in-hibition rate was drawn, and a suitable experiment concentration of 5-FU was chosen. MDA-MB-468 cells was serially passaged under continuous interference with the suitable concentration of 5-FU, 6 generations of cells were collected, cells with 5-FU interference were designed as experiment group and a corresponding control group with no 5-FU was set. RT-PCR and Western blot were employed to ex-amine mRNA and protein expression of Bmi-1 and Sca-1, Oct-4 in the 6 generations of cells of both control group and experiment group. Results Results of the MTT test showed that 5-FU could inhibit the proliferation of human breast cancer cell line MDA-MB-468, the 5-FU concentration of 0. 1 μg/ml was chosen as the suitable experiment concentration. RT-PCR tests showed that the differ-ences between the relative mRNA expression values of Bmi-1 and Sca-1, Oct-4 in the 6 generations of MDA-MB-468 cells were not sta-tistically significant in control group (all P>0. 05) and that the differences between the relative mRNA expression values of Bmi-1 and Sca-1, Oct-4 in the 6 generations of MDA-MB-468 cells were of statistical significance in experiment group cells (all P<0. 05). The mRNA expression of Bmi-1, Sca-1 and Oct-4 showed the following tendency in the 6 generations of passaged cellsdecrease (1st gen-eration)—increase (2nd generation)—continuous increase (3rd generation)—decrease (4th generation)—increase (5th genera-tion)—decrease (6th generation). Western blot tests indicated that the differences between the relative protein expression values of Bmi-1 and Sca-1, Oct-4 in the 6 generations of MDA-MB-468 cells were not statistically significant in control group and that the differ-ences between the relative protein expression values of Bmi-1 and Sca-1, Oct-4 in the 6 generations of MDA-MB-468 cells were of sta-tistical significance in experiment group cells (all P<0. 05). The expression of Bmi-1 was positively correlated with stem cell associat-ed factors Sca-1, Oct-4 (r=1, all P<0. 01). Conclusions The expression of Bmi-1 gene is positively correlated with expression of stem cell associated factors Sca-1 and Oct-4 in breast cancer cell line MDA-MB-468 cell, and Bmi-1 may be a novel marker for cancer stem cells in breast cancer. Administration of 5-FU can affect the expression level of Bmi-1 and the ration of cancer stem cells in breast cancer cell line MDA-MB-468. Bmi-1 gene may be associated with drug resistance to chemotherapy and recurrence in breast cancer.