XJTU-L453, a PI3Kα inhibitor, exhibits an IC50 of 0.4 nM. It inhibits the proliferation of breast cancer cell lines T47D and MCF7, with IC50 values of 0.2 μM and 0.5 μM respectively. Additionally, XJTU-L453 disrupts the PI3K pathway, leading to cell cycle arrest and cell apoptosis (apoptosis). It also demonstrates antitumor activity in MCF7 xenograft mice.