Discovery of thieno[2,3-d]pyrimidine-based dual Aurora B/VEGFR-2 inhibitors with potent anticancer activity: molecular docking, mechanistic studies, and in vivo validation in a breast cancer model

Breast cancer continues to be the most common malignancy in women and a major contributor of cancer-related mortality, emphasizing the need for novel therapeutic agents. A novel series of thienopyrimidine analogues were designed as dual Aurora B and VEGFR-2 inhibitors. Among them, compound M1 showed the highest potency, displaying strong cytotoxicity against breast MCF-7 (IC50 = 3.61 µM) and MDA-MB-231 (IC50 = 5.37 µM) cells, comparable to Doxorubicin and superior to Sorafenib. The in vitro enzyme inhibition assays revealed that M1 inhibited Aurora B and VEGFR-2 with IC50 values of 0.037 and 0.220 µM, respectively. In MDA-MB-231 cells, M1 induced G1-phase arrest and enhanced apoptosis, reducing viable cells to 54.6% and increasing total apoptotic cells to 21.3%. In vivo, M1 reduced tumor volume by 58.6% in a DMBA-induced breast cancer model, comparable to Doxorubicin (64.8%) but with lower systemic toxicity. Histopathology and caspase-3 staining confirmed reduced malignancy and restored apoptotic activity. Molecular docking and dynamics suggested stable binding of M1 within Aurora B and VEGFR-2 active sites.