Figure 4
The combination of MM-121 and trastuzumab induces cell cycle G1 arrest mainly associated with induction of p27kip1in two trastuzumab-resistant cell lines. SKBR3-pool2 and BT474-HR20 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, p27kip1, or β-actin. The densitometry analyses of E2F-1, Cyclin D1, and p27kip1 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 cell cycle analysis. Data show a representative of three independent experiments.