Figure 2.

PI3K inhibitors induce apoptosis in trastuzumab-resistant breast cancer cells with PIK3CA mutations or PTEN loss. A. Three cells lines were treated with alpelisib at the indicated concentrations. Cells were stained with annexin V/PI and analyzed by flow cytometry to determine the proportion of apoptotic cells. HCC1954 and HCC1569 cells were collected 48 hours after treatment, whereas UACC893 cells were analyzed at 72 hours. The x-axis indicates the intensity of annexin V, whereas the y-axis indicates PI. B. Cells lines were treated with GDC-0077 at the indicated concentrations and the proportion of apoptotic cells were analyzed. C. Lysates were collected 24 hours after alpelisib or GDC-0077 treatment and subjected to immunoblotting for detection of cleaved-PARP antibody. Equal loading of proteins was verified using beta-actin. The numbers under each blot represent the intensity of cleaved-PARP relative to that of the control. Experiments were repeated at least three times and the results are summarized as bar charts. Each bar represents the mean ± SD. P-value: *P<0.05, **P<0.01, and ***P<0.001.