Eight triple-negative breast cancer cell lines were treated with TAK228 in combination with eribulin. Cell growth was measured after 72 hours of treatment using the sulforhodamine B assay, and the combination index (CI) was then calculated using the method of Chou and Talalay. A CI value <0.8 indicates synergism, a value equal to 1 indicates additive effect, and a CI significantly>1.2 indicates antagonism. (B) MDA-MB-436 and MDA-MB-468 cells were treated with the vehicle, 50 nM TAK228, 10 nM eribulin or TAK228 in combination with eribulin. After 48 hours, cell cycle was determined with propidium iodide by fluorescence-activated cell sorting (FACS) analysis. (C) MDA-MB-436, MDA-MB-468 and MFM-223 cells were treated with the vehicle, 50 nM TAK228, 10 nM eribulin or TAK228 in combination with eribulin. After 48 hours, annexin-V-positive cells were determined by FACS analysis.