| Description: |
As previously described, after 48 h, OH-TAM significantly increased the percentage of cells in the G0/G1 phase for both ERa(+) cell lines (MCF-7, ZR-75-1) while no modification of cell cycle distribution was observed in either of the ERa negative cell lines (MDA-MB231, SKBR-3). Interestingly, Fc-OH-TAM affected cell cycle distribution differently from OH-TAM. In ERa(+) cells, 1μM of Fc-OH-TAM first increased the percentage of cells in the S phase at 24 h, and this increase was then followed by an arrest in G0/G1 at 48 h (Table 2). Fc-OH-TAM significantly increased the percentage of BrdU-positive cells (48.09%) (in the S phase) compared to what is observed for non-treated cells or for cells treated with OH-TAM (35.63%), thus indicating a cell cycle progression from G0/G1 to S phase. Next, pulse/chase experiments were performed as follows: after the 2 h incubation period in the presence of BrdU, cells were washed, left to recover for 24 h, and then analyzed .OH-TAM increased the percentage of SA-βgalactosidase cells in ERa(+) cells but not in ERa() cells, indicating that G0/G1 cell cycle arrest was associated with senescence induction in MCF-7 cells treated with OH-TAM. Interestingly, FcOH-TAM treatment increased SA-β-galactosidase staining in both cell lines (MCF-7 and MDA-MB-231). |