LA-CB1 is a derivative of Abemaciclib that targets CDK4/6 and promotes their degradation via the ubiquitin-proteasome pathway, thereby blocking the CDK4/6-Cyclin D1-Rb-E2F axis and inducing G0/G1 cell cycle arrest and apoptosis (Apoptosis). It demonstrates antiproliferative activity against MDA-MB-231 cells with an IC50 of 0.27 µM and effectively inhibits epithelial-mesenchymal transition, cell migration, invasion, and angiogenesis. In highly invasive models like triple-negative breast cancer (TNBC), LA-CB1 significantly suppresses tumor growth, showing robust dose-dependent antitumor activity. This compound can be utilized in breast cancer research.