Figure 3

The addition of MM-121 enhances trastuzumab-induced cell cycle G1 arrest in erbB2+ breast cancer cell lines. SKBR3 and BT474 cells were untreated or treated with either trastuzumab or MM-121 alone, or their combinations for 24 hrs. A, Half of the cells were collected and subjected to western blot analyses with specific antibodies directed against E2F-1, Cyclin D1, p27^kip1, or β-actin. The densitometry analyses of E2F-1, Cyclin D1, and p27^kip1 signals were shown underneath, and the arbitrary numbers indicate the intensities of each sample relative to controls, defined as 1.0. B &C, The other half of the cells were collected for analysis of cell cycle distributions by flow cytometry as described in the Materials and Methods. Data show a representative of three independent experiments.