BME inhibits breast cancer cell proliferation. Breast cancer cells (MDA-MB-231 and MCF-7) and HMECs were treated with different concentrations of BME (1%, 2%, and 5%, v/v). Cell viability was measured after 48 h by trypan blue exclusion. Columns, mean of three separate experiments. The lowest level of significance was P < 0.001.
BME-mediated cell death involves PARP cleavage and caspase activation. Lysates were prepared from MCF-7 cells (A) or MDA-MB-231 cells (B) treated with BME (2%) for 48 h and subjected to Western blot analysis using a specific antibody to PARP or caspases. After treatment of BME, PARP was cleaved to an 86-kDa signature peptide (top). Treatment of MCF-7 cells with BME induces caspase-7 (A). The antibody used in this experiment only recognized the procaspase-7 form. On the other hand, BME treatment in MDA-MB-231 cells induces caspase-3 (B; cleaved caspase-3). The blot was reprobed with an antibody to actin for comparison of equal protein load.
BME treatment in breast cancer cells inhibits survivin and claspin expression. Modulation of apoptosis signaling molecules in BME-treated MCF-7 (A) or MDA-MB-231 (B) cells. Breast cancer cells were treated with BME for 48 h and cell lysates were used for antibody array. The blot was scanned for presentation, and the data presented as pixel density. Western blot analysis was done for claspin (left) and survivin (right) expression using specific antibodies (C). The blot was reprobed with an antibody to actin for comparison of equal protein load.
Treatment of BME in MCF-7 cells resulted in accumulation of cells at the G2-M phase. A, cells were treated with BME for 6 and 24 h and stained with propidium iodide. DNA content was analyzed by flow cytometry. Results are represented as percent of cell population in G1, S, and G2-M phases of the cell cycle. P < 0.01. B, the population of cells at different cell cycle phases is shown by a bar diagram.
Modulation cell cycle regulatory proteins following BME treatment in breast cancer cells. A, MCF-7 cells were treated with BME for 24 h. Cell lysates were analyzed for the expression of cyclin D1, p53, cyclin B1, and p21 by Western blot using specific antibodies. The blots were reprobed with an antibody to actin for comparison of protein load. B, Western blot analysis was done for phosphorylated and total Chk1 and Chk2 expression of MCF-7 cells treated with BME for 48 h using specific antibodies. The blots were reprobed with an antibody to actin for comparison of equal protein load.